diff --git a/IPython/parallel/util.py b/IPython/parallel/util.py
index a688d1d..a3b011f 100644
--- a/IPython/parallel/util.py
+++ b/IPython/parallel/util.py
@@ -222,16 +222,17 @@ def interactive(f):
     This results in the function being linked to the user_ns as globals()
     instead of the module globals().
     """
-    mainmod = __import__('__main__')
     
     # build new FunctionType, so it can have the right globals
     # interactive functions never have closures, that's kind of the point
-    f2 = FunctionType(f.__code__, mainmod.__dict__,
-        f.__name__, f.__defaults__,
-    )
+    if isinstance(f, FunctionType):
+        mainmod = __import__('__main__')
+        f = FunctionType(f.__code__, mainmod.__dict__,
+            f.__name__, f.__defaults__,
+        )
     # associate with __main__ for uncanning
-    f2.__module__ = '__main__'
-    return f2
+    f.__module__ = '__main__'
+    return f
 
 @interactive
 def _push(**ns):