diff --git a/README.md b/README.md
index a95a299..2c4643d 100644
--- a/README.md
+++ b/README.md
@@ -64,6 +64,7 @@ Visit `/-/actor` when signed in to see the shape of the authenticated actor. It
 ```json
 {
     "actor": {
+        "id": "github:9599",
         "display": "simonw",
         "gh_id": "9599",
         "gh_name": "Simon Willison",
@@ -106,7 +107,7 @@ Note that GitHub allows users to change their username, and it is possible for o
 ```json
 {
     "allow": {
-        "gh_id": "9599"
+        "id": "github:9599"
     }
 }
 ```
diff --git a/datasette_auth_github/views.py b/datasette_auth_github/views.py
index 1758e5b..db9ecf5 100644
--- a/datasette_auth_github/views.py
+++ b/datasette_auth_github/views.py
@@ -76,6 +76,7 @@ async def github_auth_callback(datasette, request, scope, receive, send):
     except ValueError:
         return await response_error(datasette, "Could not load GitHub profile")
     actor = {
+        "id": "github:{}".format(profile["id"]),
         "display": profile["login"],
         "gh_id": str(profile["id"]),
         "gh_name": profile["name"],
diff --git a/tests/test_datasette_auth_github.py b/tests/test_datasette_auth_github.py
index fb9d2af..019542c 100644
--- a/tests/test_datasette_auth_github.py
+++ b/tests/test_datasette_auth_github.py
@@ -154,6 +154,7 @@ async def test_github_auth_callback(ds, mocked_github_api):
     )
     actor = ds.unsign(response.cookies["ds_actor"], "actor")["a"]
     assert {
+        "id": "github:123",
         "display": "demouser",
         "gh_id": "123",
         "gh_name": "GitHub User",