Robert Pattinson was so fearful he would screw up “Cosmopolis,” he tried to find a way to turn down the part of Wall Street financier Eric Packer, who goes on a surreal 24-hour trip that begins with an innocent limo ride across Manhattan to get a haircut.

“Cosmopolis” will be screened at the Cannes Film Festival, which is now underway in France. Rob is hoping the film establishes him as a serious actor in a way the “Twilight” films can never do.

Check out Rob’s photos; click to enlarge.

Surprisingly, despite enjoying international success with Kristen Stewart as vampire Edward Cullen in the “Twilight” film series, Pattinson still feels terribly insecure as an actor, or at least the kind of actor he wants to be.

“I was so scared I would screw this up that I spent a week trying to find a way to refuse the job,” he says in a new interview with French magazine Telerama.

“And then I told myself that I shouldn’t be so stuck-up. My agent was nervous: ‘Why would you accept [the part] if you don’t understand it?’”

Rob said he met with famed Director David Cronenberg, and decided to be totally honest. “I confessed my confusion to David and he liked it,” Rob says. “I think that might be why he hired me. Most actors would have try to act cooler, try to say something smart, but I was completely lost.”

Rob has always been known as a self-effacing individual who is brutally honest about himself and his acting ability. In this case it paid off for him.

Oddly, an unusual quirk in the production also helped Rob secure the lead in the movie. Because the movie is a partnership between France and Canada, Cronenberg told the magazine he was only allowed to hire one American actor. “For me, it was Paul Giamatti,” he said.

That created a quandary about the role of Packer. “The character is 28; he’s American. We needed someone who would look that age and that could do a perfect American accent.” His first choice was actor Colin Farrell. But when he wasn’t available, Rob came into the picture.

“Cronenberg prefered that I knew nothing [about the part],” Rob says. “He wanted me to give in, to say my lines in almost an abstract way, like poetry. It was exciting and a little scary.”

“Today, I’m nervous about the idea of having to talk to an audience about a movie that stays dark,” Rob says.

“But Cronenberg, himself, wanted to have something that escapes him. He would tell me about [Director Federico] Fellini and say that a filmmaker that has a goal is dead already,” he adds.

“It’s so much more interesting than to know right away where an artist is gonna take you. Plus, its’ the first time I really like one of the movies I make.”