diff --git a/sphinx/ext/autodoc/_directive_options.py b/sphinx/ext/autodoc/_directive_options.py
index b3f42d96fa4..8021402fe57 100644
--- a/sphinx/ext/autodoc/_directive_options.py
+++ b/sphinx/ext/autodoc/_directive_options.py
@@ -89,20 +89,6 @@ def copy(self) -> Self:
     def from_directive_options(cls, opts: Mapping[str, Any], /) -> Self:
         return cls(**{k.replace('-', '_'): v for k, v in opts.items() if v is not None})
 
-    def merge_member_options(self) -> Self:
-        """Merge :private-members: and :special-members: into :members:"""
-        if self.members is ALL:
-            # merging is not needed when members: ALL
-            return self
-
-        members = self.members or []
-        for others in self.private_members, self.special_members:
-            if others is not None and others is not ALL:
-                members.extend(others)
-        new = self.copy()
-        new.members = list(dict.fromkeys(members))  # deduplicate; preserve order
-        return new
-
 
 def identity(x: Any) -> Any:
     return x
diff --git a/sphinx/ext/autodoc/_documenters.py b/sphinx/ext/autodoc/_documenters.py
index 24c7980b045..c33cf5a4c27 100644
--- a/sphinx/ext/autodoc/_documenters.py
+++ b/sphinx/ext/autodoc/_documenters.py
@@ -100,16 +100,6 @@ def __init__(
         # the module analyzer to get at attribute docs, or None
         self.analyzer: ModuleAnalyzer | None = None
 
-        if isinstance(self, ModuleDocumenter):
-            self.options = self.options.merge_member_options()
-        elif isinstance(self, ClassDocumenter):
-            if self.config.autodoc_class_signature == 'separated':
-                # show __init__() method
-                if self.options.special_members is None:
-                    self.options.special_members = []
-                self.options.special_members += ['__new__', '__init__']
-            self.options = self.options.merge_member_options()
-
     def add_line(self, line: str, source: str, *lineno: int, indent: str) -> None:
         """Append one line of generated reST to the output."""
         if line.strip():  # not a blank line
diff --git a/sphinx/ext/autodoc/_member_finder.py b/sphinx/ext/autodoc/_member_finder.py
index de27b88dcd3..4ecc3c826eb 100644
--- a/sphinx/ext/autodoc/_member_finder.py
+++ b/sphinx/ext/autodoc/_member_finder.py
@@ -193,10 +193,13 @@ def _gather_members(
     found_members = _get_members_to_document(
         want_all=want_all,
         get_attr=get_attr,
+        class_signature=config.autodoc_class_signature,
         inherit_docstrings=config.autodoc_inherit_docstrings,
         props=props,
         opt_members=options.members or (),
         inherited_members=inherited_members,
+        opt_private_members=options.private_members,
+        opt_special_members=options.special_members,
         ignore_module_all=bool(options.ignore_module_all),
         attr_docs=attr_docs,
     )
@@ -205,6 +208,7 @@ def _gather_members(
         want_all=want_all,
         events=events,
         get_attr=get_attr,
+        class_signature=config.autodoc_class_signature,
         inherit_docstrings=config.autodoc_inherit_docstrings,
         options=options,
         props=props,
@@ -229,12 +233,10 @@ def _gather_members(
         if not obj_type:
             # don't know how to document this member
             continue
-        doccls = registry.documenters[obj_type]
         # give explicitly separated module name, so that members
         # of inner classes can be documented
         dotted_parts = '.'.join((*props.parts, member_name))
         full_name = f'{props.module_name}::{dotted_parts}'
-        documenter = doccls(directive, full_name, indent)
 
         # We now try to import all objects before ordering them. This is to
         # avoid possible circular imports if we were to import objects after
@@ -249,10 +251,13 @@ def _gather_members(
             env=env,
             events=events,
             get_attr=get_attr,
-            options=documenter.options,
+            options=directive.genopt,
         )
         if member_props is None:
             continue
+
+        doccls = registry.documenters[obj_type]
+        documenter = doccls(directive, full_name, indent)
         documenter.props = member_props
 
         member_documenters.append((documenter, is_attr))
@@ -277,10 +282,13 @@ def _get_members_to_document(
     *,
     want_all: bool,
     get_attr: _AttrGetter,
+    class_signature: Literal['mixed', 'separated'],
     inherit_docstrings: bool,
     props: _ModuleProperties | _ClassDefProperties,
     opt_members: ALL_T | Sequence[str],
     inherited_members: Set[str],
+    opt_private_members: ALL_T | Sequence[str] | None,
+    opt_special_members: ALL_T | Sequence[str] | None,
     ignore_module_all: bool,
     attr_docs: dict[tuple[str, str], list[str]],
 ) -> list[ObjectMember]:
@@ -315,7 +323,16 @@ def _get_members_to_document(
     else:
         # specific members given
         assert opt_members is not ALL
-        wanted_members = frozenset(opt_members)
+
+        # Merge :private-members: and :special-members: into :members:
+        combined_members = set(opt_members)
+        if opt_private_members is not None and opt_private_members is not ALL:
+            combined_members.update(opt_private_members)
+        if opt_special_members is not None and opt_special_members is not ALL:
+            combined_members.update(opt_special_members)
+        if class_signature == 'separated' and props.obj_type in {'class', 'exception'}:
+            combined_members |= {'__new__', '__init__'}  # show __init__() method
+        wanted_members = frozenset(combined_members)
 
     object_members_map: dict[str, ObjectMember] = {}
     if props.obj_type == 'module':
@@ -489,6 +506,7 @@ def _filter_members(
     get_attr: _AttrGetter,
     options: _AutoDocumenterOptions,
     props: _ModuleProperties | _ClassDefProperties,
+    class_signature: Literal['mixed', 'separated'],
     inherit_docstrings: bool,
     inherited_members: Set[str],
     exclude_members: EMPTY_T | Set[str] | None,
@@ -513,6 +531,7 @@ def _filter_members(
                 member_cls=obj.class_,
                 get_attr=get_attr,
                 has_attr_doc=has_attr_doc,
+                class_signature=class_signature,
                 inherit_docstrings=inherit_docstrings,
                 inherited_members=inherited_members,
                 parent=props._obj,
@@ -793,6 +812,7 @@ def _should_keep_member(
     member_cls: Any,
     get_attr: _AttrGetter,
     has_attr_doc: bool,
+    class_signature: Literal['mixed', 'separated'],
     inherit_docstrings: bool,
     inherited_members: Set[str],
     parent: Any,
@@ -862,12 +882,16 @@ def _should_keep_member(
 
     if special_member_re.match(member_name):
         # special __methods__
+        if member_name == '__doc__' or is_filtered_inherited_member:
+            return False
         if special_members and member_name in special_members:
-            if member_name == '__doc__':  # NoQA: SIM114
-                return False
-            elif is_filtered_inherited_member:
-                return False
             return has_doc
+        if (
+            class_signature == 'separated'
+            and member_name in {'__new__', '__init__'}
+            and inspect.isclass(parent)
+        ):
+            return has_doc  # show __init__() method
         return False
 
     if is_private:
diff --git a/sphinx/ext/autodoc/directive.py b/sphinx/ext/autodoc/directive.py
index 33099dc186f..3394689b551 100644
--- a/sphinx/ext/autodoc/directive.py
+++ b/sphinx/ext/autodoc/directive.py
@@ -142,10 +142,6 @@ def run(self) -> list[Node]:
 
         # generate the output
         get_attr = _AutodocAttrGetter(self.env._registry.autodoc_attrgetters)
-        params = DocumenterBridge(
-            self.env, reporter, documenter_options, lineno, self.state, get_attr
-        )
-        documenter = doccls(params, self.arguments[0])
         props = _load_object_by_name(
             name=self.arguments[0],
             objtype=objtype,  # type: ignore[arg-type]
@@ -156,11 +152,17 @@ def run(self) -> list[Node]:
             env=self.env,
             events=self.env.events,
             get_attr=get_attr,
-            options=documenter.options,
+            options=documenter_options,
+        )
+        if props is None:
+            return []
+
+        params = DocumenterBridge(
+            self.env, reporter, documenter_options, lineno, self.state, get_attr
         )
-        if props is not None:
-            documenter.props = props
-            documenter._generate(more_content=self.content)
+        documenter = doccls(params, self.arguments[0])
+        documenter.props = props
+        documenter._generate(more_content=self.content)
         if not params.result:
             return []
 
diff --git a/sphinx/ext/autosummary/__init__.py b/sphinx/ext/autosummary/__init__.py
index 474e3826962..a510fc17a2c 100644
--- a/sphinx/ext/autosummary/__init__.py
+++ b/sphinx/ext/autosummary/__init__.py
@@ -369,7 +369,6 @@ def get_items(self, names: list[str]) -> list[tuple[str, str | None, str, str]]:
 
             result = StringList()  # initialize for each documenter
             obj_type = _get_documenter(obj, parent)
-            doccls = env._registry.documenters[obj_type]
             if isinstance(obj, ModuleType):
                 full_name = real_name
             else:
@@ -379,7 +378,6 @@ def get_items(self, names: list[str]) -> list[tuple[str, str | None, str, str]]:
             # NB. using full_name here is important, since Documenters
             #     handle module prefixes slightly differently
             self.bridge.result = result
-            documenter = doccls(self.bridge, full_name)
             props = _load_object_by_name(
                 name=full_name,
                 objtype=obj_type,
@@ -390,7 +388,7 @@ def get_items(self, names: list[str]) -> list[tuple[str, str | None, str, str]]:
                 env=env,
                 events=events,
                 get_attr=get_attr,
-                options=documenter.options,
+                options=self.bridge.genopt,
             )
             if props is None:
                 logger.warning(
@@ -400,7 +398,6 @@ def get_items(self, names: list[str]) -> list[tuple[str, str | None, str, str]]:
                 )
                 items.append((display_name, '', '', real_name))
                 continue
-            documenter.props = props
 
             # try to also get a source code analyzer for attribute docs
             real_module = props._obj___module__ or props.module_name
@@ -413,7 +410,6 @@ def get_items(self, names: list[str]) -> list[tuple[str, str | None, str, str]]:
                 logger.debug('[autodoc] module analyzer failed: %s', err)
                 # no source file -- e.g. for builtin and C modules
                 analyzer = None
-            documenter.analyzer = analyzer
 
             # -- Grab the signature
 
@@ -429,6 +425,10 @@ def get_items(self, names: list[str]) -> list[tuple[str, str | None, str, str]]:
 
             # -- Grab the summary
 
+            doccls = env._registry.documenters[obj_type]
+            documenter = doccls(self.bridge, full_name)
+            documenter.props = props
+            documenter.analyzer = analyzer
             documenter.add_content(None, indent=documenter.indent)
             lines = result.data[:]
             if props.obj_type != 'module':
diff --git a/tests/test_ext_autodoc/autodoc_util.py b/tests/test_ext_autodoc/autodoc_util.py
index 6e9a086341f..f559e0a95d3 100644
--- a/tests/test_ext_autodoc/autodoc_util.py
+++ b/tests/test_ext_autodoc/autodoc_util.py
@@ -3,6 +3,8 @@
 from typing import TYPE_CHECKING
 from unittest.mock import Mock
 
+from docutils.statemachine import StringList
+
 from sphinx.ext.autodoc._directive_options import (
     _AutoDocumenterOptions,
     _process_documenter_options,
@@ -17,8 +19,6 @@
 if TYPE_CHECKING:
     from typing import Any
 
-    from docutils.statemachine import StringList
-
     from sphinx.application import Sphinx
     from sphinx.ext.autodoc._property_types import _AutodocObjType
 
@@ -38,12 +38,7 @@ def do_autodoc(
         default_options=app.config.autodoc_default_options,
         options=options,
     )
-    docoptions = _AutoDocumenterOptions.from_directive_options(opts)
-    state = Mock()
-    bridge = DocumenterBridge(
-        app.env, LoggingReporter(''), docoptions, 1, state, safe_getattr
-    )
-    documenter = doccls(bridge, name)
+    doc_options = _AutoDocumenterOptions.from_directive_options(opts)
     props = _load_object_by_name(
         name=name,
         objtype=obj_type,
@@ -54,9 +49,16 @@ def do_autodoc(
         env=app.env,
         events=app.events,
         get_attr=safe_getattr,
-        options=documenter.options,
+        options=doc_options,
     )
+    result = StringList()
     if props is not None:
+        state = Mock()
+        bridge = DocumenterBridge(
+            app.env, LoggingReporter(''), doc_options, 1, state, safe_getattr
+        )
+        bridge.result = result
+        documenter = doccls(bridge, name)
         documenter.props = props
         documenter._generate()
-    return bridge.result
+    return result
diff --git a/tests/test_ext_autodoc/test_ext_autodoc.py b/tests/test_ext_autodoc/test_ext_autodoc.py
index 5238d5be583..34aea68ca0b 100644
--- a/tests/test_ext_autodoc/test_ext_autodoc.py
+++ b/tests/test_ext_autodoc/test_ext_autodoc.py
@@ -598,8 +598,6 @@ def _special_getattr(obj, attr_name, *defargs):
 def _assert_getter_works(app, directive, objtype, name, *attrs):
     getattr_spy.clear()
 
-    doccls = app.registry.documenters[objtype]
-    documenter = doccls(directive, name)
     props = _load_object_by_name(
         name=name,
         objtype=objtype,
@@ -610,9 +608,11 @@ def _assert_getter_works(app, directive, objtype, name, *attrs):
         env=app.env,
         events=app.events,
         get_attr=directive.get_attr,
-        options=documenter.options,
+        options=directive.genopt,
     )
     if props is not None:
+        doccls = app.registry.documenters[objtype]
+        documenter = doccls(directive, name)
         documenter.props = props
         documenter._generate()