diff --git a/src/script/script.h b/src/script/script.h
--- a/src/script/script.h
+++ b/src/script/script.h
@@ -468,7 +468,7 @@
         return ret;
     }
 
-    CScript(int64_t b) { operator<<(b); }
+    explicit CScript(int64_t b) { operator<<(b); }
 
     explicit CScript(opcodetype b) { operator<<(b); }
     explicit CScript(const CScriptNum &b) { operator<<(b); }