diff --git a/src/endpoints/movies.ts b/src/endpoints/movies.ts
index 6d5c60f..2db92c0 100644
--- a/src/endpoints/movies.ts
+++ b/src/endpoints/movies.ts
@@ -35,7 +35,7 @@ export class MoviesEndpoint extends BaseEndpoint {
     super(accessToken);
   }
 
-  async details<T extends AppendToResponseMovieKeys[]>(
+  async details<T extends AppendToResponseMovieKeys[] | undefined>(
     id: number,
     appendToResponse?: T
   ) {
diff --git a/src/endpoints/people.ts b/src/endpoints/people.ts
index e50e067..7689b03 100644
--- a/src/endpoints/people.ts
+++ b/src/endpoints/people.ts
@@ -23,7 +23,7 @@ export class PeopleEndpoint extends BaseEndpoint {
     super(accessToken);
   }
 
-  async details<T extends AppendToResponsePersonKeys[]>(
+  async details<T extends AppendToResponsePersonKeys[] | undefined>(
     id: number,
     appendToResponse?: T
   ) {
diff --git a/src/endpoints/tv-shows.ts b/src/endpoints/tv-shows.ts
index f0d21fb..65b0508 100644
--- a/src/endpoints/tv-shows.ts
+++ b/src/endpoints/tv-shows.ts
@@ -37,7 +37,7 @@ export class TvShowsEndpoint extends BaseEndpoint {
     super(accessToken);
   }
 
-  async details<T extends AppendToResponseTvKeys[]>(
+  async details<T extends AppendToResponseTvKeys[] | undefined>(
     id: number,
     appendToResponse?: T
   ) {