diff --git a/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsMediaSource.java b/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsMediaSource.java
index 8e8c5aca19..00bd81d754 100644
--- a/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsMediaSource.java
+++ b/extensions/ima/src/main/java/com/google/android/exoplayer2/ext/ima/ImaAdsMediaSource.java
@@ -506,7 +506,7 @@ public final class ImaAdsMediaSource implements MediaSource {
 
     @Override
     public boolean continueLoading(long positionUs) {
-      return mediaPeriod.continueLoading(positionUs);
+      return mediaPeriod != null && mediaPeriod.continueLoading(positionUs);
     }
 
     // MediaPeriod.Callback implementation.