diff --git a/crates/ruma-client-api/CHANGELOG.md b/crates/ruma-client-api/CHANGELOG.md
index ed9fa07e..cbdee709 100644
--- a/crates/ruma-client-api/CHANGELOG.md
+++ b/crates/ruma-client-api/CHANGELOG.md
@@ -19,6 +19,10 @@ Bug fixes:
 
 - Rename `avatar` to `avatar_url` when (De)serializing
 
+Bug fixes:
+
+- `user_id` of `SlidingSyncRoomHero` is now mandatory
+
 # 0.18.0
 
 Bug fixes:
diff --git a/crates/ruma-client-api/src/sync/sync_events/v4.rs b/crates/ruma-client-api/src/sync/sync_events/v4.rs
index 7873f76c..2a6a56c6 100644
--- a/crates/ruma-client-api/src/sync/sync_events/v4.rs
+++ b/crates/ruma-client-api/src/sync/sync_events/v4.rs
@@ -504,12 +504,11 @@ impl SlidingSyncRoom {
 }
 
 /// A sliding sync room hero.
-#[derive(Clone, Debug, Default, Deserialize, Serialize)]
+#[derive(Clone, Debug, Deserialize, Serialize)]
 #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]
 pub struct SlidingSyncRoomHero {
     /// The user ID of the hero.
-    #[serde(skip_serializing_if = "Option::is_none")]
-    pub user_id: Option<OwnedUserId>,
+    pub user_id: OwnedUserId,
 
     /// The name of the hero.
     #[serde(rename = "displayname", skip_serializing_if = "Option::is_none")]
@@ -520,6 +519,13 @@ pub struct SlidingSyncRoomHero {
     pub avatar: Option<OwnedMxcUri>,
 }
 
+impl SlidingSyncRoomHero {
+    /// Creates a new `SlidingSyncRoomHero` with the given user id.
+    pub fn new(user_id: OwnedUserId) -> Self {
+        Self { user_id, name: None, avatar: None }
+    }
+}
+
 /// Sliding-Sync extension configuration.
 #[derive(Clone, Debug, Default, Serialize, Deserialize, PartialEq)]
 #[cfg_attr(not(feature = "unstable-exhaustive-types"), non_exhaustive)]