diff --git a/src/core/index.js b/src/core/index.js
index 00a796d32..d6a4d64b5 100644
--- a/src/core/index.js
+++ b/src/core/index.js
@@ -38,11 +38,12 @@ export function setup(id, clientID, domain, options, hookRunner, emitEventFn) {
     hashCleanup: options.hashCleanup === false ? false : true,
     allowedConnections: Immutable.fromJS(options.allowedConnections || []),
     ui: extractUIOptions(id, options),
-    defaultADUsernameFromEmailPrefix: options.defaultADUsernameFromEmailPrefix === false ? false : true
+    defaultADUsernameFromEmailPrefix: options.defaultADUsernameFromEmailPrefix === false ? false : true,
+    prefill: options.prefill || {}
   }));
 
   m = i18n.initI18n(m);
-
+  
   return m;
 }
 
@@ -365,6 +366,10 @@ export function defaultADUsernameFromEmailPrefix(m) {
   return get(m, "defaultADUsernameFromEmailPrefix", true);
 }
 
+export function prefill(m) {
+  return get(m, "prefill", {});
+}
+
 export function warn(x, str) {
   const shouldOutput = Map.isMap(x)
     ? !ui.disableWarnings(x)
diff --git a/src/engine/classic.js b/src/engine/classic.js
index 66c773202..33fbc108c 100644
--- a/src/engine/classic.js
+++ b/src/engine/classic.js
@@ -97,6 +97,13 @@ function validateAllowedConnections(m) {
   return m;
 }
 
+const setPrefill = m => {
+  const { email, username } = l.prefill(m).toJS();
+  if (typeof email === "string") m = setEmail(m, email);
+  if (typeof username === "string") m = setUsername(m, username, "username", false);
+  return m;
+}
+
 class Classic {
 
   static SCREENS = {
@@ -111,15 +118,13 @@ class Classic {
     model = initDatabase(model, options);
     model = initEnterprise(model, options);
 
-    const { email, username } = options.prefill || {};
-    if (typeof email === "string") model = setEmail(model, email);
-    if (typeof username === "string") model = setUsername(model, username, "username", false);
-
     return model;
   }
 
   didReceiveClientSettings(m) {
-    return validateAllowedConnections(m);
+    m = validateAllowedConnections(m);
+    m = setPrefill(m);
+    return m;
   }
 
   willShow(m, opts) {
diff --git a/support/index.html b/support/index.html
index a1c9dbb3b..0fcfdc8a6 100644
--- a/support/index.html
+++ b/support/index.html
@@ -20,6 +20,7 @@
     };
 
     const lock = new Auth0Lock(cid, domain, options);
+    window.lock = lock;
 
     lock.on("authenticated", function(authResult) {
       console.log(authResult);