Sienna Miller and Sam Worthington have joined the cast of the horizon, 

including Kevin Costner and Jamie Campbell Bower

The creators of the horizon had already announced Kevin Costner and Jamie Campbell as the cast

 but Sienna Miller and Sam Worthington are the new names.

Horizon is an American historical epic, and the project is very close to the heart of

Kevin Costner. he is once again going to hold the chair of directors since 2003.

The movie is more about pre and posts civil war

 expansion and settlements of the American West.

As for the media reports, Horizon is going to be the first installment of the planned trilogy

Both stars, Sienna Miller and Sam Burlington have been part of several great 

movies, including American sniper and avatar, respectively

Both actors have mentioned in their statements that they are

very excited to join this epic journey. Costner is an Academy-Award winning director,

 so we can expect something great from him.