diff --git a/direct/src/interval/MopathInterval.py b/direct/src/interval/MopathInterval.py
index 0b0f9bf1d2..fe16700fc9 100644
--- a/direct/src/interval/MopathInterval.py
+++ b/direct/src/interval/MopathInterval.py
@@ -35,6 +35,10 @@ class MopathInterval(LerpInterval.LerpFunctionInterval):
         self.mopath = mopath 
         self.node = node
 
+    def destroy(self):
+        """Cleanup to avoid a garbage cycle."""
+        self.function = None
+
     def __doMopath(self, t):
         """
         Go to time t