Justin Bieber gestures during a Toronto news conference Tuesday for his documentary film Never Say Never. (Darren Calabrese/Canadian Press)

Justin Bieber says he's a "regular teenaged boy" living out a dream.

In Toronto on Tuesday to promote his upcoming movie Justin Bieber: Never Say Never, the Grammy-nominated singer said the film is really an answer to the many naysayers who believe he's a flash-in-the-pan pop star.

"A lot of people think that I'm just some machine and people put me together as a product, but I worked really hard to get here and there's so many people that helped me," Bieber said.

The film, directed by Jon M. Chu, shows the Stratford, Ont.-born singer learning both guitar and drums from the age of six.

It follows the teen from street performer to internet phenomenon to his sold-out show at Madison Square Garden last year.

A poised Bieber, 16, told a news conference he hopes the film will show people he worked at learning music and writing songs.

"There's going to be haters no matter what. People want to see you succeed and then once you're there they want to bring you down. It's a weird world, but that's just how it is," he said.

Bieber was fresh off an appearance Monday evening on Late Show with David Letterman, where he showed the talk-show host how to use Twitter.

The young singer has 6.9 million followers on Twitter, which he says he uses to keep in touch with fans.

"Twitter is a wonderful thing because I can interact with my fans. They feel they are part of me," he said, adding that fan adoration doesn't bother him because he'd be nowhere without the fans.

The film Justin Bieber: Never Say Never was to have a fan screening later Tuesday and will open across Canada on Feb. 11.