Ashton Kutcher and Anne Heche
Angela Weiss/WireImage; Jason Merritt/Getty
08/10/2009 AT 10:05 AM EDT
How did Ashton Kutcher
and Anne Heche prepare to shoot their explicit new film Spread
? By scurrying to the gym and slimming down.
"I did everything I possibly could to give him a run for his money onscreen," Heche, 40, told PEOPLE at Saturday night's premiere of the movie in East Hampton, N.Y. "I ran and I did a few more sit-ups than normal ... and stayed away from the butter."
Kutcher, 31, who plays a hustler sleeping his way into a life of privilege (and seducing Heche's character along the way), likewise dropped weight. "I had just played a movie [Personal Effects
] where I played a wrestler," he told PEOPLE, "so I had to lose like 10 pounds and stop eating and take care of myself. I really cut back to a meal a day. I was probably down to 175 pounds."
Heche said she also wanted to look good next to the film's third costar, Margarita Levieva, who is a full decade Heche's junior. Both actresses credited Kutcher's wife, Demi Moore
, for her support of the sexually charged project.
"Demi was there a lot," Levieva said. " She was kind to me. She wasn't there to freak us out or anything. She was incredibly kind and generous and made me feel safe."
Added Heche: "I worked with [Moore] on The Juror
, and there was an intimacy that she needed [with the new film]. I don't think it's a mistake that she and I had been friends. There needs to be trust there when you send your guy off to work."
The actors said they took the sexual nature of their roles seriously. "We wanted to create something that nobody's ever done before," Heche said. "We wanted to be more outrageous and dangerous. Nobody was joking around about it."
"We entered into these scenes and said, 'What are we going to do to make this honest?'" said Kutcher. "It's our job."
How did Moore, 46, feel about the finished product? "I'm a big fan of the movie," she told PEOPLE.
Saturday's premiere was sponsored by Niche Media and Gotham