Ashton Kutcher** definitely suffered for his art. To realistically channel the late Apple Inc. founder Steve Jobs in biopic jOBS, the actor, 34, went to extreme lengths: Watching "hundreds of hours" of footage, scouring the visionary's speeches, interviewing Jobs' friends . . . and even copying his "fruitarian diet," Kutcher told the Associated Press at the Sundance Film Festival premiere of the film in Park City, Utah on Friday Jan. 25.

The choice to go "fruitarian" -- consuming only fruits, nuts and seeds and no animal products, vegetables or grains -- "can lead to some serious problems," Kutcher revealed. Indeed, as a result, Kutcher "ended up in the hospital two days before we started shooting the movie," he said.

"I was like doubled over in pain, and my pancreas levels were completely out of whack, which was completely terrifying, considering everything," said the That 70s Show alum. (Jobs died in October 2011 at age 56 of pancreatic cancer.)

The pain was worth it, Kutcher (a tech entrepreneur himself) insisted to Us Weekly at Friday's red carpet, which he attended without love Mila Kunis**. Not that he isn't a little nervous about the reception to the film: "It's portraying a guy who just passed away that is really fresh in people's minds ,that people are really passionate about, and care about, and have an opinion about -- that's really scary," he confessed. "Especially portraying a guy that I really admire . . . it's terrifying, it's terrifying!"

This article originally appeared on Usmagazine.com: Ashton Kutcher Was Hospitalized After Adopting "Fruitarian Diet" for Steve Jobs Movie