diff --git a/stepmania/src/LuaReference.cpp b/stepmania/src/LuaReference.cpp
index f3a6c13aed..c98ba715be 100644
--- a/stepmania/src/LuaReference.cpp
+++ b/stepmania/src/LuaReference.cpp
@@ -76,6 +76,26 @@ void LuaReference::SetFromNil()
 	m_iReference = LUA_REFNIL;
 }
 
+void LuaReference::DeepCopy()
+{
+	/* Call DeepCopy(t), where t is our referenced object. */
+	Lua *L = LUA->Get();
+	lua_pushstring( L, "DeepCopy" );
+	lua_gettable( L, LUA_GLOBALSINDEX );
+
+	ASSERT_M( !lua_isnil(L, -1), "DeepCopy() missing" );
+	ASSERT_M( lua_isfunction(L, -1), "DeepCopy() not a function" );
+
+	/* Arg 1 (t): */
+	this->PushSelf( L );
+
+	lua_call( L, 1, 1 );
+
+	this->SetFromStack( L );
+
+	LUA->Release( L );
+}
+
 void LuaReference::PushSelf( lua_State *L ) const
 {
 	lua_rawgeti( L, LUA_REGISTRYINDEX, m_iReference );
diff --git a/stepmania/src/LuaReference.h b/stepmania/src/LuaReference.h
index cc011a77a2..c13b5b0074 100644
--- a/stepmania/src/LuaReference.h
+++ b/stepmania/src/LuaReference.h
@@ -21,6 +21,9 @@ public:
 	void SetFromStack( Lua *L );
 	void SetFromNil();
 
+	/* Deep-copy tables, detaching this reference from any others. */
+	void DeepCopy();
+
 	/* Push the referenced object onto the stack.  If not set (or set to nil), push nil. */
 	virtual void PushSelf( Lua *L ) const;