TORONTO -- In taking on the role of a 35-year-old who has an affair with his girlfriend's 15-year-old daughter, Alexander Skarsgard says he didn't want to "play him too predatory."

After all, the young attention-starved protagonist in the film, "The Diary of a Teenage Girl," isn't portrayed as a victim.

Rather, the budding teenaged cartoonist takes charge of her own sexuality and wants to initiate the relationship with her mother's boyfriend.

Marielle Heller wrote and directed the story, which is set in 1976-era San Francisco and based on the novel by Phoebe Gloeckner.

Skarsgard says he wanted to find moments where the connection between his character, Monroe, and teenager Minnie (played by Bel Powley) was "deep and real and beautiful."

He also wanted to "make it more layered and more difficult for the audience to just hate him," since the balance of control in the relationship between Monroe and Minnie is always shifting.

"I saw Monroe as, in many ways, a teenager himself and that was my way into the character," Skarsgard says in a phone interview.

"I felt that that was a way of really connecting him and Minnie, because I think if he's a teenager himself, we can find moments where they're actually just two teenagers that are in love."

"The Diary of a Teenage Girl" debuted to rave reviews at the Sundance Film Festival and opens Friday in Toronto and Vancouver. It will hit Montreal on Aug. 28.

Kristen Wiig plays Minnie's mother and Christopher Meloni plays the ex-stepdad.

Skarsgard says he got the script from his friend, who is close with Heller. He found it "so unique and different and brave."

"It was really refreshing to read a coming-of-age story that's so out there and so honest from a girl's point of view," said the former "True Blood" star.

"I felt like there's been so many stories about adolescent boys ... and thinking about sex and getting laid, but you whenever you portray a girl at that age it's so prude in a way, and I just thought that can't represent how young girls feel."

Added Skarsgard: "I thought it was so cool to read a script where the girl was just like: 'I want to get laid and I don't know what's going on with me and what's happening in my head,' that it was a story about a teenager girl that wasn't too precocious or 'I want to find a nice husband and two children and a dog."'

He was also intrigued by his character and ultimately found him "difficult to play."

Before shooting began in San Francisco, he, Powley and Heller hung out every day together "to know each other on a personal level," he said.

When it came to the nudity and sex scenes, Skarsgard was comfortable, feeling it was intrinsic to the storytelling (plus, Powley is actually 23).

"I don't think anyone can watch this film and say that nudity or the sex is gratuitous," he said. "It's done in a beautiful way and those pieces are important to the puzzle."

Skarsgard fans were in a frenzy on social media recently when he showed up to the film's premiere in San Francisco dressed in drag.

He said it was in honour of the legendary San Francisco drag queens who worked on the movie and hosted the screening and after-party.

The drag queens did his makeup and helped make his dress, which he admitted wasn't easy to wear along with heels.

"I was in the military in Sweden for a month and a half but these guys are way tougher than I was," said Skarsgard.

"Walking around in that is really painful. It was pretty intense. I have a whole new level of appreciation for drag queens."