The Hollywood star has already taken out a mortgage on 10 acres of his waterfront property in California to help fund the film project, which tells of the challenges faced by settlers expanding the American West in the late 1800s. Now, he needs more financial backing for the project.
"If we all went out together into this harbour and we stood in front of one boat. And didn't let those rich people off, and we can tell them, 'Look, you can dress up, you can walk on the red carpet,' you know..." Costner told a packed news conference.
"I have knocked on every boat in Cannes to help me. They say 'Ooh, come have a picture', I say 'No, come get your chequebook out. I want to see. Let's talk money," he added.
The first two parts are complete, with the 181-minute initial chapter premiering out of competition at the festival on Sunday. It will be released in North America and select European locations on June 28, followed by part two on Aug. 16.
Filming on the third chapter began before Costner set out for Cannes.
"This has been so hard. And it's not over yet," he told Reuters in an interview at the festival.
MIXED REVIEWS
Costner will star in, direct, produce and co-write the film series, which covers a 15-year period before and after the 1861-1865 Civil War when white settlers expanded westward in the United States, taking land from American Indians.
Costner's previous credits in Westerns include his Oscar-winning "Dances With Wolves" in 1990 and more recently as the star of the successful five-season TV series "Yellowstone."
"I can't fill every box every time I try to make a movie, but I'm absolutely conscious of what's at stake, and trying to represent people," Costner said at the news conference.
"Horizon," with Sienna Miller, Jena Malone, Abbey Lee and Dale Dickey among the cast, is also heavily oriented towards women, added Costner.
Reviews trended towards the negative, with Britain's The Guardian newspaper calling it "a big vain slog up familiar old west alleys," while another British newspaper, The Telegraph, said it would please those who pine for old-fashioned Westerns.
"Costner may have just invented granddad cinema," read The Telegraph headline.
