Kevin Costner wants to split 'Horizon' into "four different movies".

The 67-year-old star has opened up on plans for his epic Western - which is set to go into production by the end of August and will be his fourth directorial effort - and he hopes to bring out a new film "about every three months".

Revealing he has the project planned as "four different movies", he told Variety: "They’re all different films that all connect, so you’re watching a saga of these storylines that are happening."

He revealed casting for the movie - his first as director since 2003's 'Open Rage', following 'The Post Man' in 1997 and 1990's 'Dances With Wolves' - is underway as the team is "trying to fill up" 170 speaking roles.

And with the film being split into four parts, Costner described the project as being sold as an "event television movie", but he noted the studio will make the final decision on whether it comes to streaming or the big screen.

He explained: "I’m happiest because at one point in TV — where you can get your largest audience — they’re going to get to see it the way I intended it to be seen.

"It will eventually be cut up into [hour-long episodes] or 42 minutes — however TV works. But their first viewing of it will be as four 2 hour and 45-minute movies. And every three months, one will come out.

"If you’re interested in those characters, the hope is that you’ll really want to watch the next one, but it won’t be in hour segments.”

'Horizon' is set to span 15 years in the settlement of America's Western frontier, while he wants to focus on both settlers and Indigenous groups.

He said: "It’s a really beautiful story; it’s a hard story. It really involves a lot of women, to be honest.

"There are a lot of men in it, too, but the women are really strong in ‘Horizon.’ It’s just them trying to get by every day in a world that was impossibly tough."