diff --git a/content/client-server-api/modules/guest_access.md b/content/client-server-api/modules/guest_access.md
index 8b4c985c635..d789424a61e 100644
--- a/content/client-server-api/modules/guest_access.md
+++ b/content/client-server-api/modules/guest_access.md
@@ -64,6 +64,7 @@ for their own account maintenance:
 -   [GET /devices](#get_matrixclientv3devices)
 -   [GET /devices/{deviceId}](#get_matrixclientv3devicesdeviceid)
 -   [PUT /devices/{deviceId}](#put_matrixclientv3devicesdeviceid)
+-   {{% added-in v="1.2" %}} [GET /account/whoami](#get_matrixclientv3accountwhoami)
 
 The following API endpoints are allowed to be accessed by guest accounts
 for end-to-end encryption:
diff --git a/data/api/client-server/whoami.yaml b/data/api/client-server/whoami.yaml
index d53ed158127..727f7e642f8 100644
--- a/data/api/client-server/whoami.yaml
+++ b/data/api/client-server/whoami.yaml
@@ -65,6 +65,13 @@ paths:
                   is associated with the access token (such as in the case
                   of application services) then this field can be omitted.
                   Otherwise this is required.
+              is_guest:
+                x-addedInMatrixVersion: "1.2"
+                type: boolean
+                description: |-
+                  When `true`, the user is a [Guest User](#guest-access). When
+                  not present or `false`, the user is presumed to be a non-guest
+                  user.
         401:
           description:
             The token is not recognised