diff --git a/src/blocks/scratch3_sensing.js b/src/blocks/scratch3_sensing.js
index b19e4a368..f140997cf 100644
--- a/src/blocks/scratch3_sensing.js
+++ b/src/blocks/scratch3_sensing.js
@@ -68,6 +68,7 @@ class Scratch3SensingBlocks {
             sensing_loud: this.isLoud,
             sensing_askandwait: this.askAndWait,
             sensing_answer: this.getAnswer,
+            sensing_username: this.getUsername,
             sensing_userid: () => {} // legacy no-op block
         };
     }
@@ -315,6 +316,11 @@ class Scratch3SensingBlocks {
         // Otherwise, 0
         return 0;
     }
+
+    getUsername () {
+        // Logged out users get empty string. Return that for now.
+        return '';
+    }
 }
 
 module.exports = Scratch3SensingBlocks;
diff --git a/test/unit/blocks_sensing.js b/test/unit/blocks_sensing.js
index e791d38d5..cf607d3b9 100644
--- a/test/unit/blocks_sensing.js
+++ b/test/unit/blocks_sensing.js
@@ -143,3 +143,11 @@ test('loud? boolean', t => {
 
     t.end();
 });
+
+test('username block', t => {
+    const rt = new Runtime();
+    const sensing = new Sensing(rt);
+
+    t.equal(sensing.getUsername(), '');
+    t.end();
+});