diff --git a/tests/integration/test_aiohttp.py b/tests/integration/test_aiohttp.py
index bbb0913..8f3b743 100644
--- a/tests/integration/test_aiohttp.py
+++ b/tests/integration/test_aiohttp.py
@@ -56,6 +56,8 @@ def test_headers(tmpdir, scheme):
         cassette_response, _ = get(url)
         assert cassette_response.headers == response.headers
         assert cassette.play_count == 1
+        assert 'istr' not in cassette.data[0]
+        assert 'yarl.URL' not in cassette.data[0]
 
 
 def test_text(tmpdir, scheme):
diff --git a/vcr/stubs/aiohttp_stubs/__init__.py b/vcr/stubs/aiohttp_stubs/__init__.py
index 237ddea..6de1c17 100644
--- a/vcr/stubs/aiohttp_stubs/__init__.py
+++ b/vcr/stubs/aiohttp_stubs/__init__.py
@@ -98,9 +98,9 @@ def vcr_request(cassette, real_request):
                 'code': response.status,
                 'message': response.reason,
             },
-            'headers': dict(response.headers),
+            'headers': {str(key): value for key, value in response.headers.items()},
             'body': {'string': (await response.read())},  # NOQA: E999
-            'url': response.url,
+            'url': str(response.url),
         }
         cassette.append(vcr_request, vcr_response)