diff --git a/src/blocks/scratch3_looks.js b/src/blocks/scratch3_looks.js
index 70ffd777d..df1a0246e 100644
--- a/src/blocks/scratch3_looks.js
+++ b/src/blocks/scratch3_looks.js
@@ -240,7 +240,7 @@ class Scratch3LooksBlocks {
 
     say (args, util) {
         // @TODO in 2.0 calling say/think resets the right/left bias of the bubble
-        this._updateBubble(util.target, 'say', args.MESSAGE);
+        this._updateBubble(util.target, 'say', String(args.MESSAGE));
     }
 
     sayforsecs (args, util) {
@@ -256,7 +256,7 @@ class Scratch3LooksBlocks {
     }
 
     think (args, util) {
-        this._updateBubble(util.target, 'think', args.MESSAGE);
+        this._updateBubble(util.target, 'think', String(args.MESSAGE));
     }
 
     thinkforsecs (args, util) {