diff --git a/app/lib/activitypub/adapter.rb b/app/lib/activitypub/adapter.rb
index 2edad1caa..7b0b1390c 100644
--- a/app/lib/activitypub/adapter.rb
+++ b/app/lib/activitypub/adapter.rb
@@ -36,6 +36,10 @@ class ActivityPub::Adapter < ActiveModelSerializers::Adapter::Base
       'mp' => 'https://monsterpit.net/ns#',
       'supportsChat' => 'mp:supportsChat'
     },
+    locked: {
+      'mp' => 'https://monsterpit.net/ns#',
+      'locked' => 'mp:locked'
+    },
   }.freeze
 
   def self.default_key_transform
diff --git a/app/serializers/activitypub/actor_serializer.rb b/app/serializers/activitypub/actor_serializer.rb
index a260a6f1f..95110bfc2 100644
--- a/app/serializers/activitypub/actor_serializer.rb
+++ b/app/serializers/activitypub/actor_serializer.rb
@@ -7,14 +7,14 @@ class ActivityPub::ActorSerializer < ActivityPub::Serializer
 
   context_extensions :manually_approves_followers, :featured, :also_known_as,
                      :moved_to, :property_value, :hashtag, :emoji, :identity_proof,
-                     :adult_content, :gently, :kobold, :supports_chat
+                     :adult_content, :gently, :kobold, :supports_chat, :locked
 
   attributes :id, :type, :following, :followers,
              :inbox, :outbox, :featured,
              :preferred_username, :name, :summary,
              :url, :manually_approves_followers,
              :gently, :kobold, :adult_content,
-             :supports_chat
+             :supports_chat, :locked
 
   has_one :public_key, serializer: ActivityPub::PublicKeySerializer