diff --git a/library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java b/library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java
index 7167ebe8be..d6543810e5 100644
--- a/library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java
+++ b/library/core/src/main/java/com/google/android/exoplayer2/SimpleExoPlayer.java
@@ -980,6 +980,7 @@ public class SimpleExoPlayer extends BasePlayer
 
   @Override
   public void release() {
+    verifyApplicationThread();
     audioFocusManager.handleStop();
     player.release();
     removeSurfaceCallbacks();