diff --git a/libavcodec/anm.c b/libavcodec/anm.c
index 72684189bb..ab6a3994e9 100644
--- a/libavcodec/anm.c
+++ b/libavcodec/anm.c
@@ -54,7 +54,7 @@ static av_cold int decode_init(AVCodecContext *avctx)
 
     bytestream2_skipu(&s->gb, 16 * 8);
     for (i = 0; i < 256; i++)
-        s->palette[i] = bytestream2_get_le32u(&s->gb);
+        s->palette[i] = (0xFFU << 24) | bytestream2_get_le32u(&s->gb);
 
     return 0;
 }