‘WHAT I really like is that the [characters] evolve from screwing to love.”

That’s Meg Ryan’s defense of her latest movie, “In the Cut,” a hot, bloody, erotic thriller that features steamy, nude sex scenes between her and co-star Mark Ruffalo.

In the film, which made its world premiere last night at the Toronto International Film Festival (it opens nationally on Oct. 24th), Ryan plays a spinsterish writing professor who’s attracted to Ruffalo, a kinky police detective tracking a brutal serial killer in lower Manhattan, despite – or perhaps because of – her growing suspicions that the twisted detective himself may be responsible for the crimes.

The 41-year-old former queen of romantic comedies scoffs at suggestions by journalists that she agreed to bare her breasts and buttocks to revitalize her flagging career – and put her cutie-pie image behind her for good.

“You all can say what you want,” she said, referring to the press, which gave her film a decidedly mixed reception.

“I’ve done 30 movies and I’ve done seven romantic comedies. So I don’t know what the typical Meg Ryan movie is.”

In fact, Ryan has been naked before, in 1987’s “Promised Land,” and had a clothed sex scene in the thriller “Flesh and Bone.”

But she is far better known for comedies like “Sleepless in Seattle” and “You’ve Got Mail,” her last box-office hit.

Her last movie, the romantic comedy “Kate & Leopold,” flopped two years ago, and “Against the Ropes,” in which she plays against type as a boxing manager, is currently scheduled for release next February – nearly a year after it was originally slated to come out.

Explaining her decision to sign on for “In the Cut,” she said, “It was the right movie with the right director,” referring to Australia’s Jane Campion, best known for art films like “The Piano.”

“There are some things in the movie that were much more difficult than the sex scenes, like playing a character who doesn’t talk much, which is something new for me,” Ryan said.

“Jane didn’t want the [sex scenes] to be coy,” said Ryan. “They were not fun at all to shoot, though Mark and I did laugh a lot.”

Jennifer Jason Leigh, who plays Ryan’s sister in the movie, admits that for audiences “it’s a shock for [Ryan] to do this. But she does it like nobody’s business. She’s jaw-droppingly good.”

“I think it was actually kind of easy for her” to do the sex scenes, Leigh added. “It just wasn’t asked of her before.”

Ruffalo, who is five years younger than Ryan, said the lovemaking “was really well choreographed. We had two weeks of rehearsals and countless hours of talking with Jane about what she was looking for.”

The results were originally so explicit, the movie was threatened with a highly restrictive NC-17 rating until cuts were made.

“I was shocked at the reaction,” said Ruffalo.

“For me, what these two people are engaging in is not so different than what most of us do in private. I mean, it was disturbing to the ratings board that I used the word ‘clitoris’ in a line of dialogue.”

“In the Cut” was originally supposed to star Nicole Kidman, who purchased the film rights to Susanna Moore’s novel, but passed on the role in the wake of her breakup with ex-hubby Tom Cruise.

“I wasn’t in an emotional state to be able to play that role at that time,” said Kidman, who is credited as one of the movie’s producers.

“I wanted to be with my children. It was a very painful thing to give up.

“At the same time, I was very glad for Meg Ryan to be given what I consider is such a complicated female role – and I think she is so good in the movie.”