diff --git a/lib/script/witness.js b/lib/script/witness.js
index c4ed87a3b..30f34ed1f 100644
--- a/lib/script/witness.js
+++ b/lib/script/witness.js
@@ -409,7 +409,7 @@ class Witness extends Stack {
     bw.writeVarint(this.items.length);
 
     for (const item of this.items)
-      bw.writeVarBytes(item);
+      bw.writeVarBytes(Buffer.from(item));
 
     return bw;
   }