diff --git a/sphinx/directives.py b/sphinx/directives.py
index 903c3dadc..498a1bc8c 100644
--- a/sphinx/directives.py
+++ b/sphinx/directives.py
@@ -133,10 +133,12 @@ def parse_py_signature(signode, sig, desctype, env):
     if m is None: raise ValueError
     classname, name, arglist = m.groups()
 
+    add_module = True
     if env.currclass:
         if classname and classname.startswith(env.currclass):
             fullname = classname + name
             classname = classname[len(env.currclass):].lstrip('.')
+            add_module = False
         elif classname:
             fullname = env.currclass + '.' + classname + name
         else:
@@ -148,7 +150,7 @@ def parse_py_signature(signode, sig, desctype, env):
         signode += addnodes.desc_classname(classname, classname)
     # exceptions are a special case, since they are documented in the
     # 'exceptions' module.
-    elif env.config.add_module_names and \
+    elif add_module and env.config.add_module_names and \
            env.currmodule and env.currmodule != 'exceptions':
         nodetext = env.currmodule + '.'
         signode += addnodes.desc_classname(nodetext, nodetext)