{babes} Natalie Portman & Mila Kunis Talk Girl-on-Girl Sex Scene

We'll get to Natalie Portman and Mila Kunis' Black Swan sex scene in a sec, but first let's talk about their trips to the hospital while making the movie.

The two may have trained boot-camp style for their roles as New York ballerinas, but...

"I tore a ligament," Kunis told us last night at the film's AFI Fest 2010 screening presented by Audi in L.A. "I hyperextended my shoulder. I had to go get an MRI. I have a couple of scars, a couple of bruises."

Portman was injured at the hands of costar Vincent Cassel. No, he didn't do it on purpose. "Natalie had a rib injury from being carried by Vincent, who had very little training on how to lift," said Benjamin Millepied, who not only plays a principal dancer in Black Swan but served as director Darren Aronofsky's choreographer. "We repeated a scene so many times, the next day he couldn't walk because his back was bad, and she couldn't breathe because her rib was bad from [being] squeezed. Her rib was just out of place.

"There's a moment in the film where she's with a therapist who inserts her fingers in her rib. It's actually real. She was actually really working on her."

Portman also ended up at the hospital for an X-ray and MRI because she fell and "hit her head pretty good," said producer Brian Oliver.

Now about that much-talked-about sex scene...

"It was awkward and we laughed," Portman said. "It was strange, but it's something you just sort of throw yourself into."

Kunis said, "It's as awkward as any sex scene. They're always going to be a little awkward."

And we're happy to report that rumors of Portman's dad not being too happy about the girl-on-girl action appear to be bogus. "My parents saw [the movie] and they loved it," Portman said. "I was so honored because they're the ones I care most about. I was completely nervous while they were watching it and they really loved it."

And we loved how Portman and Kunis looked last night. Portman wore a floral chiffon Rodarte dress (the fashion house designed the movie's ballet costumes) while Kunis was super chic in a black Oscar de la Renta number.