There are various ways of making movie history.

You can usher in the sound era, as Al Jolson did more than 80 years ago with The Jazz Singer.

Or you can create an enduring Hollywood epic, as producer David O. Selznick did with Gone with the Wind.

Or you can be Walt Disney, defying the Hollywood naysayers and his own bankers by risking all with a full-length animated feature like Snow White and the Seven Dwarfs.

And then, of course, there's the naked ambition of Jason Segel who made his own kind of screen history by stumbling about in last year's Forgetting Sarah Marshall, the first mainstream Hollywood movie to give full frontal male nudity more than a passing glance.

"You know, I think for some reason I was born without a sense of shame or regret," Segel laughs. "I sort of have been my whole life."

The 29-year-old actor continues to display his affection for unspeakable behaviour in the upcoming I Love You, Man, the new DreamWorks comedy about the unorthodox male friendship which develops between a young but introverted real estate agent, played by Paul Rudd, and a fun-loving, womanizing bachelor, portrayed by Segel, who exercises a slobbish disregard for the normal rules of conduct.

Segel is a fixture on the CBS comedy series, How I Met Your Mother, but the defining moment of his career was Forgetting Sarah Marshall and the scene in which his girlfriend dumps him while he's naked. Functioning as both star and writer of the screenplay, Segel was only too happy to grant the filmmaker Judd Apatow's desire for a full frontal nudity sequence.

"The nudity was a calculated decision," he remembers happily, even though he needed several drinks to get through the scene. It was also a decision which helped raise Sarah Marshall's earnings above the $100 million level. And it seems he was drawing on a real-life experience.

"I was dumped once while naked, and when it was happening, I was aware that it was the funniest thing ever - so I needed to recreate it."

Besides, Segel thinks the world needs more romantic comedies which go the unorthodox route. That's why he loved doing Forgetting Sarah Marshall, and that's why he's so keen on I Love You, Man, which opens March 20.

"I'm always reticent to go to romantic comedies because I know what's going to happen. The guy is going to end up with the girl. So I thought that if, in the opening scene of a movie, the main character is all of a sudden completely naked, you're sort of forcing the audience member to say - all right, I don't know what's going to happen in this movie, so you throw out all your preconceptions and sit back and watch it."

Co-star Paul Rudd likens Segel to a combination of an insane person and a golden retriever.

"There's such a lovable floppiness about him," Rudd tells Canwest News Service. "He's like a golden retriever who jumps on your lap, but he can also on the turn of a dime, totally on a dime, have this crazy look in his eye, and you don't know if he might kill you."

Segel, who's sitting beside Rudd this morning, can't resist a fast comeback.

"I think I reveal my lovable floppiness in the opening scene of Sarah Marshall," he quips.

In their new film, Rudd plays Peter Klaven, a successful real estate agent who is soon to marry the woman of his dreams, played by Rashida Jones, but realizes to his dismay that he has no close male friend to serve as his best man.

"Really, for the first time, he realizes he doesn't have any close male friendships," Rudd says. "All my friendships are born out of my relationship with my fiancee. They're really her friends."

Peter embarks on a series of disastrous "man dates" in an embarrassing quest for a new male friend capable of serving as his best man. And then, by chance, on the day he throws an open house for one of his clients, he meets slobbish Sydney Fife (Segel) who spends his weekends cruising open houses in search of free food and lonely divorcees. The two click, despite Sydney's outrageous behaviour, and a friendship slowly develops - but it's one which also threatens Peter's looming marriage.

"My guy is the exact opposite of Peter - he's shunned matrimony his whole life," Segel explains. "He doesn't really want to be that close to a woman, and he doesn't feel that he can share with a woman as well as he can share with his guy friends . . . so being around dudes is where he's more comfortable. But he's reaching a point in his life where all his guy friends are getting married and he's being left alone. So when Peter arrives he's sort of a godsend for my character - a guy who could be a replacement friend."

Trouble is - Sydney would put a strain on any relationship. He lets his dog - named Anwar Sadat because he looks like the late Egyptian president - dump on the sidewalk, and then refuses to pick up after it. He shows up at a family engagement dinner, and in an impromptu speech almost kills off the engagement when he amiably chides the love of Peter's life for not being adventurous enough sexually.

And then there's the raunchy moment when he regales an incredulous Peter with an account of the pleasures of self-gratification.

Director John Hamburg is responsible for the screenplay of I Love You, Man, but Segel cheerfully admits he could happily have written these scenes himself. His own lack of inhibition is now a mainstay of his persona - and he credits longtime buddy Judd Apatow, with whom he has worked for more than a decade, for his ease with being outrageous on screen.

"Judd has been slowly undressing me on screen for 10 years," he reports. "In Freaks and Geeks, he had me in just underwear. In Undeclared, he had me in a towel. In Knocked up, he had me covering myself when naked. And with Sarah Marshall, he finally got what he needed."

But Apatow also gave Segel valuable advice which sustained him when he was making I Love You, Man.

"One of the things Judd told me about when I was younger and in Freaks and Geeks was how to maintain likability without crossing the creepy line. So I sort of enjoy pushing those boundaries and seeing how far I can go without having the audience turn on me."

Both Rudd and Segel are excited about their new film, but beyond the zany comedy, they also think it has something important to say about male friendships by going to a level more meaningful than that of a conventional "buddy" movie. They think it provides a useful reminder that a deep male friendship doesn't have to be sexual and that Hollywood should stop shying away from such situations.

"It's a pretty universal issue, and it's sort of been avoided," Segel says. "I don't know why the subject is taboo."