diff --git a/src/dobjtype.cpp b/src/dobjtype.cpp
index bf3a6773f..9420a939f 100644
--- a/src/dobjtype.cpp
+++ b/src/dobjtype.cpp
@@ -1180,6 +1180,7 @@ void PClass::InsertIntoHash ()
 	{ // This type has already been inserted
 	  // ... but there is no need whatsoever to make it a fatal error!
 		Printf (TEXTCOLOR_RED"Tried to register class '%s' more than once.\n", TypeName.GetChars());
+		TypeTable.ReplaceType(this, found, bucket);
 	}
 	else
 	{
@@ -1471,6 +1472,31 @@ PType *FTypeTable::FindType(PClass *metatype, intptr_t parm1, intptr_t parm2, si
 	return NULL;
 }
 
+//==========================================================================
+//
+// FTypeTable :: ReplaceType
+//
+// Replaces an existing type in the table with a new version of the same
+// type. For use when redefining actors in DECORATE. Does nothing if the
+// old version is not in the table.
+//
+//==========================================================================
+
+void FTypeTable::ReplaceType(PType *newtype, PType *oldtype, size_t bucket)
+{
+	for (PType **type_p = &TypeHash[bucket]; *type_p != NULL; type_p = &(*type_p)->HashNext)
+	{
+		PType *type = *type_p;
+		if (type == oldtype)
+		{
+			newtype->HashNext = type->HashNext;
+			type->HashNext = NULL;
+			*type_p = newtype;
+			break;
+		}
+	}
+}
+
 //==========================================================================
 //
 // FTypeTable :: AddType - Fully Parameterized Version
diff --git a/src/dobjtype.h b/src/dobjtype.h
index a3b41e12d..b04f7fce5 100644
--- a/src/dobjtype.h
+++ b/src/dobjtype.h
@@ -561,6 +561,7 @@ struct FTypeTable
 	PType *TypeHash[HASH_SIZE];
 
 	PType *FindType(PClass *metatype, intptr_t parm1, intptr_t parm2, size_t *bucketnum);
+	void ReplaceType(PType *newtype, PType *oldtype, size_t bucket);
 	void AddType(PType *type, PClass *metatype, intptr_t parm1, intptr_t parm2, size_t bucket);
 	void AddType(PType *type);
 	void Mark();