diff --git a/AsyncDisplayKit/ASMultiplexImageNode.h b/AsyncDisplayKit/ASMultiplexImageNode.h
index 2178893f35..31e2276351 100644
--- a/AsyncDisplayKit/ASMultiplexImageNode.h
+++ b/AsyncDisplayKit/ASMultiplexImageNode.h
@@ -225,7 +225,7 @@ didFinishDownloadingImageWithIdentifier:(ASImageIdentifier)imageIdentifier
  * @note This method may be called from any thread.
  * @return A PHAsset corresponding to `assetLocalIdentifier`, or nil if none is available.
  */
-- (PHAsset *)multiplexImageNode:(ASMultiplexImageNode *)imageNode assetForLocalIdentifier:(NSString *)assetLocalIdentifier;
+- (nullable PHAsset *)multiplexImageNode:(ASMultiplexImageNode *)imageNode assetForLocalIdentifier:(NSString *)assetLocalIdentifier;
 
 @end