diff --git a/deno/rest/v10/channel.ts b/deno/rest/v10/channel.ts
index d77109ed..f260fa61 100644
--- a/deno/rest/v10/channel.ts
+++ b/deno/rest/v10/channel.ts
@@ -584,13 +584,22 @@ export type RESTPostAPIChannelMessagesThreadsJSONBody = AddUndefinedToPossiblyUn
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody &
-	RESTPostAPIChannelMessageJSONBody;
+export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: RESTPostAPIChannelMessageJSONBody;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessageFormDataBody;
+export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: string;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-from-message
diff --git a/deno/rest/v9/channel.ts b/deno/rest/v9/channel.ts
index fa98f33a..3aab0b94 100644
--- a/deno/rest/v9/channel.ts
+++ b/deno/rest/v9/channel.ts
@@ -598,13 +598,22 @@ export type RESTPostAPIChannelMessagesThreadsJSONBody = AddUndefinedToPossiblyUn
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody &
-	RESTPostAPIChannelMessageJSONBody;
+export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: RESTPostAPIChannelMessageJSONBody;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessageFormDataBody;
+export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: string;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-from-message
diff --git a/rest/v10/channel.ts b/rest/v10/channel.ts
index f333831b..08691db3 100644
--- a/rest/v10/channel.ts
+++ b/rest/v10/channel.ts
@@ -584,13 +584,22 @@ export type RESTPostAPIChannelMessagesThreadsJSONBody = AddUndefinedToPossiblyUn
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody &
-	RESTPostAPIChannelMessageJSONBody;
+export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: RESTPostAPIChannelMessageJSONBody;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessageFormDataBody;
+export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: string;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-from-message
diff --git a/rest/v9/channel.ts b/rest/v9/channel.ts
index f278028c..175d6f3c 100644
--- a/rest/v9/channel.ts
+++ b/rest/v9/channel.ts
@@ -598,13 +598,22 @@ export type RESTPostAPIChannelMessagesThreadsJSONBody = AddUndefinedToPossiblyUn
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody &
-	RESTPostAPIChannelMessageJSONBody;
+export type RESTPostAPIGuildForumThreadsJSONBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: RESTPostAPIChannelMessageJSONBody;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-in-forum-channel
  */
-export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessageFormDataBody;
+export type RESTPostAPIGuildForumThreadsFormDataBody = RESTPostAPIChannelMessagesThreadsJSONBody & {
+	/**
+	 * First message in the forum thread
+	 */
+	message: string;
+};
 
 /**
  * https://discord.com/developers/docs/resources/channel#start-thread-from-message