diff --git a/tests/conftest.py b/tests/conftest.py
index 777b2073847..1e70ad48065 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -487,6 +487,8 @@ def aiohttp_client(
         if isinstance(__param, Application):
             server_kwargs = server_kwargs or {}
             server = TestServer(__param, loop=loop, **server_kwargs)
+            # Registering a view after starting the server should still work.
+            server.app._router.freeze = lambda: None
             client = CoalescingClient(server, loop=loop, **kwargs)
         elif isinstance(__param, BaseTestServer):
             client = TestClient(__param, loop=loop, **kwargs)
diff --git a/tests/test_test_fixtures.py b/tests/test_test_fixtures.py
index 1c0fe0a7eaa..eb2103d4272 100644
--- a/tests/test_test_fixtures.py
+++ b/tests/test_test_fixtures.py
@@ -1,10 +1,16 @@
 """Test test fixture configuration."""
+from http import HTTPStatus
 import socket
 
+from aiohttp import web
 import pytest
 import pytest_socket
 
+from homeassistant.components.http import HomeAssistantView
 from homeassistant.core import HomeAssistant, async_get_hass
+from homeassistant.setup import async_setup_component
+
+from .typing import ClientSessionGenerator
 
 
 def test_sockets_disabled() -> None:
@@ -27,3 +33,38 @@ async def test_hass_cv(hass: HomeAssistant) -> None:
     in the fixture and that async_get_hass() works correctly.
     """
     assert async_get_hass() is hass
+
+
+def register_view(hass: HomeAssistant) -> None:
+    """Register a view."""
+
+    class TestView(HomeAssistantView):
+        """Test view to serve the test."""
+
+        requires_auth = False
+        url = "/api/test"
+        name = "api:test"
+
+        async def get(self, request: web.Request) -> web.Response:
+            """Return a test result."""
+            return self.json({"test": True})
+
+    hass.http.register_view(TestView())
+
+
+async def test_aiohttp_client_frozen_router_view(
+    hass: HomeAssistant,
+    hass_client: ClientSessionGenerator,
+) -> None:
+    """Test aiohttp_client fixture patches frozen router for views."""
+    assert await async_setup_component(hass, "http", {})
+    await hass.async_block_till_done()
+
+    # Registering the view after starting the server should still work.
+    client = await hass_client()
+    register_view(hass)
+
+    response = await client.get("/api/test")
+    assert response.status == HTTPStatus.OK
+    result = await response.json()
+    assert result["test"] is True