diff --git a/CHANGELOG.md b/CHANGELOG.md
index 86e9079a..e160af34 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,8 +8,11 @@ The format is based on the [KeepAChangeLog] project.
 ## Unreleased
 ### Changed
 - [#847] Using pydantic for settings instead of custom class
+- [#851], [#852] Add `authn_method` to `Consumer.complete`
 
 [#847]: https://github.com/CZ-NIC/pyoidc/pull/847
+[#851]: https://github.com/CZ-NIC/pyoidc/issues/851
+[#852]: https://github.com/CZ-NIC/pyoidc/pull/852
 
 ## 1.5.0 [2022-12-14]
 
diff --git a/src/oic/oic/consumer.py b/src/oic/oic/consumer.py
index f246820a..b7cc7498 100644
--- a/src/oic/oic/consumer.py
+++ b/src/oic/oic/consumer.py
@@ -461,7 +461,7 @@ def parse_authz(
             self.verify_id_token(idt, self.authz_req.get(_state or atr["state"]))
         return aresp, atr, idt
 
-    def complete(self, state):
+    def complete(self, state, authn_method: str = "client_secret_basic"):
         """
         Do the access token request, the last step in a code flow.
 
@@ -485,7 +485,10 @@ def complete(self, state):
             raise PyoidcError("Nothing to authenticate with")
 
         resp = self.do_access_token_request(
-            state=state, request_args=args, http_args=http_args
+            state=state,
+            request_args=args,
+            http_args=http_args,
+            authn_method=authn_method,
         )
 
         logger.info("Access Token Response: %s" % sanitize(resp))