diff --git a/direct/src/interval/FunctionInterval.py b/direct/src/interval/FunctionInterval.py
index e432c7cf98..272063d27f 100644
--- a/direct/src/interval/FunctionInterval.py
+++ b/direct/src/interval/FunctionInterval.py
@@ -77,7 +77,7 @@ class FunctionInterval(Interval.Interval):
 
     @staticmethod
     def makeUniqueName(func, suffix = ''):
-        name = 'Func-%s-%d' % (func.__name__, FunctionInterval.functionIntervalNum)
+        name = 'Func-%s-%d' % (getattr(func, '__name__', str(func)), FunctionInterval.functionIntervalNum)
         FunctionInterval.functionIntervalNum += 1
         if suffix:
             name = '%s-%s' % (name, str(suffix))