diff --git a/packages/babel-helpers/src/helpers.js b/packages/babel-helpers/src/helpers.js
index 0329ff4dd0..42e840f056 100644
--- a/packages/babel-helpers/src/helpers.js
+++ b/packages/babel-helpers/src/helpers.js
@@ -600,7 +600,9 @@ helpers.taggedTemplateLiteralLoose = defineHelper(`
 `);
 
 helpers.temporalRef = defineHelper(`
-  export default function _temporalRef(val, name, undef) {
+  import undef from "temporalUndefined";
+
+  export default function _temporalRef(val, name) {
     if (val === undef) {
       throw new ReferenceError(name + " is not defined - temporal dead zone");
     } else {
diff --git a/packages/babel-plugin-transform-es2015-block-scoping/src/tdz.js b/packages/babel-plugin-transform-es2015-block-scoping/src/tdz.js
index 457efe58e9..b1da159b80 100644
--- a/packages/babel-plugin-transform-es2015-block-scoping/src/tdz.js
+++ b/packages/babel-plugin-transform-es2015-block-scoping/src/tdz.js
@@ -16,7 +16,6 @@ function buildTDZAssert(node, file) {
   return t.callExpression(file.addHelper("temporalRef"), [
     node,
     t.stringLiteral(node.name),
-    file.addHelper("temporalUndefined"),
   ]);
 }