diff --git a/stepmania/src/ScreenGameplay.cpp b/stepmania/src/ScreenGameplay.cpp
index 4ec93542cb..d682009f8e 100644
--- a/stepmania/src/ScreenGameplay.cpp
+++ b/stepmania/src/ScreenGameplay.cpp
@@ -1128,6 +1128,7 @@ float ScreenGameplay::StartPlayingSong(float MinTimeToNotes, float MinTimeToMusi
 	p.StopMode = RageSoundParams::M_CONTINUE;
 	p.m_StartSecond = fStartSecond;
 
+	ASSERT( !m_pSoundMusic->IsPlaying() );
 	m_pSoundMusic->Play( &p );
 
 	/* Make sure GAMESTATE->m_fMusicSeconds is set up. */