diff --git a/package-lock.json b/package-lock.json
index f7a6e118..29206c48 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,7 +8,7 @@
       "devDependencies": {
         "@seamapi/fake-seam-connect": "1.85.0",
         "@seamapi/nextlove-sdk-generator": "^1.19.0",
-        "@seamapi/types": "1.573.0",
+        "@seamapi/types": "1.575.0",
         "del": "^7.1.0",
         "prettier": "^3.2.5"
       }
@@ -475,9 +475,9 @@
       }
     },
     "node_modules/@seamapi/types": {
-      "version": "1.573.0",
-      "resolved": "https://registry.npmjs.org/@seamapi/types/-/types-1.573.0.tgz",
-      "integrity": "sha512-EAvQwslJCQy3DfWh5/3UHpp8xcpdvw/T9IGQuamzLA2edloN7H/WNyaoqyVgZEOVV+ROyQYFcdIPYL2FwuIfSQ==",
+      "version": "1.575.0",
+      "resolved": "https://registry.npmjs.org/@seamapi/types/-/types-1.575.0.tgz",
+      "integrity": "sha512-I0QT8L6xxBNK6DBDOPU0jxRSY20CVPZdr/6kbQbPXCnIzY6vs+ZAX9Kq9gMLF3Mu5MHE9+JgDImr5Qn+5A9mxw==",
       "dev": true,
       "license": "MIT",
       "engines": {
diff --git a/package.json b/package.json
index 77400c27..d288c994 100644
--- a/package.json
+++ b/package.json
@@ -12,7 +12,7 @@
   "devDependencies": {
     "@seamapi/fake-seam-connect": "1.85.0",
     "@seamapi/nextlove-sdk-generator": "^1.19.0",
-    "@seamapi/types": "1.573.0",
+    "@seamapi/types": "1.575.0",
     "del": "^7.1.0",
     "prettier": "^3.2.5"
   }
diff --git a/seam/routes/models.py b/seam/routes/models.py
index 4f32d7fc..d308eaf3 100644
--- a/seam/routes/models.py
+++ b/seam/routes/models.py
@@ -2769,7 +2769,13 @@ def temperature_reached(
 class AbstractUserIdentities(abc.ABC):
 
     @abc.abstractmethod
-    def add_acs_user(self, *, acs_user_id: str, user_identity_id: str) -> None:
+    def add_acs_user(
+        self,
+        *,
+        acs_user_id: str,
+        user_identity_id: Optional[str] = None,
+        user_identity_key: Optional[str] = None
+    ) -> None:
         raise NotImplementedError()
 
     @abc.abstractmethod
diff --git a/seam/routes/user_identities.py b/seam/routes/user_identities.py
index 37b87c7c..cc54762a 100644
--- a/seam/routes/user_identities.py
+++ b/seam/routes/user_identities.py
@@ -15,13 +15,21 @@ def __init__(self, client: SeamHttpClient, defaults: Dict[str, Any]):
         self.client = client
         self.defaults = defaults
 
-    def add_acs_user(self, *, acs_user_id: str, user_identity_id: str) -> None:
+    def add_acs_user(
+        self,
+        *,
+        acs_user_id: str,
+        user_identity_id: Optional[str] = None,
+        user_identity_key: Optional[str] = None
+    ) -> None:
         json_payload = {}
 
         if acs_user_id is not None:
             json_payload["acs_user_id"] = acs_user_id
         if user_identity_id is not None:
             json_payload["user_identity_id"] = user_identity_id
+        if user_identity_key is not None:
+            json_payload["user_identity_key"] = user_identity_key
 
         self.client.post("/user_identities/add_acs_user", json=json_payload)