Why Chris Pratt nearly turned down his biggest role

Chris Pratt.

Guardians of the Galaxy was the film that turned Chris Pratt from TV comedian to bona fide movie star - but the actor revealed he very nearly turned down the role.

The 37-year-old star was at the time best-known for his role as goofy Andy Dwyer in TV sitcom Parks and Recreation, and underwent a massive physical transformation to become the buff Star-Lord, Peter Quill, in the 2014 hit film.

It recast the funnyman as a bona fide Hollywood heart-throb, to the surprise of many - and in a new interview withVanity Fair, Pratt himself says he wasn't sure if he could pull off the career change.

"Guardians had come around, and I passed," he told the mag.

"[The film's director] James Gunn passed on me, too. When they announced it, I looked it up and saw a list of the top 20 dudes in Hollywood who might play Peter Quill. I was not on that list. I did not want to go in and embarrass myself. My agent said, 'Guardians is everything you've been saying you want to do.' I said, 'F***, you're right'."

Pratt said that when he auditioned for the role, director Gunn was less than impressed that he'd come along.

"Jim Gunn, the way he tells it is like this: 'Who do we have next? Chris Pratt? What the f***? I said we weren't going to audition the chubby guy from Parks and Rec.'"

However, he won the director over by inhabiting the character of Peter Quill throughout the entire audition, giving his best confident, smart-alec responses to show how he could nail the character.

"Once you get smart about auditioning, you learn to audition before they say 'Action'. You walk into the room as the character. You let them think the person you are is close to the character they want. You make them think you already are that guy. Gunn was like, 'Damn, this is it'."

The rest is history - since the movie's release in 2014, Pratt led last year's smash hit Jurassic World and will next be seen in the sequel to Guardians, set for release in May. But Pratt admitted that even when he first watched the film, he wasn't sure if he'd pulled off his action hero transition.

"When it started, I was like, This is f***in' awesome! Then I saw the first scene of myself dancing and kicking rats, and I was like, Oh, my God, disaster. This movie is gonna suck. I was just so hypercritical of myself. Then the next scene comes on and you see Rocket and Groot, and I was like, Wait a minute - this movie might be really f***in' good," he said.