diff --git a/news/2 Fixes/7638.md b/news/2 Fixes/7638.md
new file mode 100644
index 000000000000..dea499b65438
--- /dev/null
+++ b/news/2 Fixes/7638.md	
@@ -0,0 +1 @@
+Fix a hang in the Interactive window when connecting guest to host after the host has already started the interactive window.
\ No newline at end of file
diff --git a/src/client/datascience/jupyter/jupyterServer.ts b/src/client/datascience/jupyter/jupyterServer.ts
index afef002f8bec..6830b2497e37 100644
--- a/src/client/datascience/jupyter/jupyterServer.ts
+++ b/src/client/datascience/jupyter/jupyterServer.ts
@@ -169,6 +169,10 @@ export class JupyterServerBase implements INotebookServer {
         return this.notebooks.get(resource.toString());
     }
 
+    protected getNotebooks(): INotebook[] {
+        return [...this.notebooks.values()];
+    }
+
     protected setNotebook(resource: Uri, notebook: INotebook) {
         const oldDispose = notebook.dispose;
         notebook.dispose = () => {
diff --git a/src/client/datascience/jupyter/liveshare/guestJupyterServer.ts b/src/client/datascience/jupyter/liveshare/guestJupyterServer.ts
index 4acea881452c..64924bce0a3b 100644
--- a/src/client/datascience/jupyter/liveshare/guestJupyterServer.ts
+++ b/src/client/datascience/jupyter/liveshare/guestJupyterServer.ts
@@ -72,6 +72,17 @@ export class GuestJupyterServer
         return result;
     }
 
+    public async onSessionChange(api: vsls.LiveShare | null): Promise<void> {
+        await super.onSessionChange(api);
+
+        this.notebooks.forEach(async notebook => {
+            const guestNotebook = notebook as GuestJupyterNotebook;
+            if (guestNotebook) {
+                await guestNotebook.onSessionChange(api);
+            }
+        });
+    }
+
     public async getNotebook(resource: Uri): Promise<INotebook | undefined> {
         return this.notebooks.get(resource.toString());
     }
diff --git a/src/client/datascience/jupyter/liveshare/hostJupyterServer.ts b/src/client/datascience/jupyter/liveshare/hostJupyterServer.ts
index 64ea465df7a1..4f099e945a19 100644
--- a/src/client/datascience/jupyter/liveshare/hostJupyterServer.ts
+++ b/src/client/datascience/jupyter/liveshare/hostJupyterServer.ts
@@ -95,6 +95,17 @@ export class HostJupyterServer
         }
     }
 
+    public async onSessionChange(api: vsls.LiveShare | null): Promise<void> {
+        await super.onSessionChange(api);
+
+        this.getNotebooks().forEach(async notebook => {
+            const hostNotebook = notebook as HostJupyterNotebook;
+            if (hostNotebook) {
+                await hostNotebook.onSessionChange(api);
+            }
+        });
+    }
+
     public async onDetach(api: vsls.LiveShare | null): Promise<void> {
         await super.onDetach(api);
 
diff --git a/src/test/datascience/liveshare.functional.test.tsx b/src/test/datascience/liveshare.functional.test.tsx
index 27ea390bac19..1ff19cafed39 100644
--- a/src/test/datascience/liveshare.functional.test.tsx
+++ b/src/test/datascience/liveshare.functional.test.tsx
@@ -202,6 +202,23 @@ suite('DataScience LiveShare tests', () => {
         verifyHtmlOnCell(guestContainer.wrapper!, 'InteractiveCell', '<span>1</span>', CellPosition.Last);
     });
 
+    test('Host starts LiveShare after starting Jupyter', async() => {
+       addMockData(hostContainer!, 'a=1\na', 1);
+       addMockData(hostContainer!, 'b=2\nb', 2);
+       await getOrCreateInteractiveWindow(vsls.Role.Host);
+       let wrapper = await addCodeToRole(vsls.Role.Host, 'a=1\na');
+       verifyHtmlOnCell(wrapper, 'InteractiveCell', '<span>1</span>', CellPosition.Last);
+
+       await startSession(vsls.Role.Host);
+       await getOrCreateInteractiveWindow(vsls.Role.Guest);
+       await startSession(vsls.Role.Guest);
+
+       wrapper = await addCodeToRole(vsls.Role.Host, 'b=2\nb');
+
+       assert.ok(guestContainer.wrapper, 'Guest wrapper not created');
+       verifyHtmlOnCell(guestContainer.wrapper!, 'InteractiveCell', '<span>2</span>', CellPosition.Last);
+    });
+
     test('Host Shutdown and Run', async () => {
         // Should only need mock data in host
         addMockData(hostContainer!, 'a=1\na', 1);