diff --git a/README.md b/README.md
index 9eb47845..336b6f13 100644
--- a/README.md
+++ b/README.md
@@ -198,7 +198,8 @@ extensions.userLoggedOut();
 
 const callInfo = {
   phoneNumber: string, // optional unless call is initiated by the widget
-  createEngagement: true // whether HubSpot should create an engagement for this call
+  createEngagement: true, // whether HubSpot should create an engagement for this call
+  callStartTime: number // optional unless call is initiated by the widget
 };
 extensions.outgoingCall(callInfo);
 ```
diff --git a/demos/demo-react-ts/src/components/screens/KeypadScreen.tsx b/demos/demo-react-ts/src/components/screens/KeypadScreen.tsx
index bb131a49..974b85fb 100644
--- a/demos/demo-react-ts/src/components/screens/KeypadScreen.tsx
+++ b/demos/demo-react-ts/src/components/screens/KeypadScreen.tsx
@@ -86,11 +86,13 @@ function KeypadScreen({
   };
 
   const handleStartCall = useCallback(() => {
+    const callStartTime = Date.now();
     cti.outgoingCall({
       createEngagement: true,
       phoneNumber: dialNumber,
+      callStartTime,
     });
-    startTimer(Date.now());
+    startTimer(callStartTime);
     handleNextScreen();
   }, [cti]);
 
diff --git a/demos/demo-react-ts/test/spec/components/screens/KeypadScreen-test.tsx b/demos/demo-react-ts/test/spec/components/screens/KeypadScreen-test.tsx
index 356b1148..3d075319 100644
--- a/demos/demo-react-ts/test/spec/components/screens/KeypadScreen-test.tsx
+++ b/demos/demo-react-ts/test/spec/components/screens/KeypadScreen-test.tsx
@@ -84,7 +84,7 @@ describe("KeypadScreen", () => {
 
     it("Handles start call button click", () => {
       const { getByRole, getByTestId } = renderWithContext(
-        <KeypadScreen {...props} />
+        <KeypadScreen {...props} dialNumber="+1617" />
       );
 
       const input = getByTestId("VizExInput-Input");
@@ -96,7 +96,12 @@ describe("KeypadScreen", () => {
         name: /start-call/i,
       });
       button.click();
-      expect(cti.outgoingCall).toHaveBeenCalled();
+
+      expect(cti.outgoingCall).toHaveBeenCalledWith({
+        createEngagement: true,
+        phoneNumber: "+1617",
+        callStartTime: jasmine.anything(),
+      });
       expect(props.handleNextScreen).toHaveBeenCalled();
     });
   });