diff --git a/src/managers/RelationshipManager.js b/src/managers/RelationshipManager.js
index bf3f099..5c33159 100644
--- a/src/managers/RelationshipManager.js
+++ b/src/managers/RelationshipManager.js
@@ -159,14 +159,14 @@ class RelationshipManager {
   /**
    * Sends a friend request.
    * @param {string} username Username of the user to send the request to
-   * @param {number} discriminator Discriminator of the user to send the request to
+   * @param {?number} discriminator Discriminator of the user to send the request to
    * @returns {Promise<boolean>}
    */
   async sendFriendRequest(username, discriminator) {
     await this.client.api.users('@me').relationships.post({
       data: {
         username,
-        discriminator: parseInt(discriminator),
+        discriminator: discriminator == 0 ? null : parseInt(discriminator),
       },
       headers: {
         'X-Context-Properties': Buffer.from(JSON.stringify({ location: 'Add Friend' }), 'utf8').toString('base64'),
diff --git a/typings/index.d.ts b/typings/index.d.ts
index 4e2eb70..1e8447c 100644
--- a/typings/index.d.ts
+++ b/typings/index.d.ts
@@ -4410,7 +4410,7 @@ export class RelationshipManager {
   public fetch(user: UserResolvable, options?: BaseFetchOptions): Promise<RelationshipTypes>;
   public deleteFriend(user: UserResolvable): Promise<boolean>;
   public deleteBlocked(user: UserResolvable): Promise<boolean>;
-  public sendFriendRequest(username: string, discriminator: number): Promise<boolean>;
+  public sendFriendRequest(username: string, discriminator?: number): Promise<boolean>;
   public cancelFriendRequest(user: UserResolvable): Promise<boolean>;
   public addFriend(user: UserResolvable): Promise<boolean>;
   public addBlocked(user: UserResolvable): Promise<boolean>;