Kevin Costner not returning to 'Yellowstone': 'It was something that really changed me'

Kevin Costner announced Thursday night through Instagram that he will not return for another season of ‘Yellowstone.’ 

"Hi, everyone. I just want to reach out and let you know that after this long year and a half of working on Horizon, and doing all the things that that's required, and thinking about Yellowstone, that beloved series that I love and I know you love. I just realized that I'm not going to be able to continue Season 5, or into the future," Costner says in his post. 

"It was something that really changed me.