"It was very satisfying and cathartic. I feel like it's for the sisters," says Portman with a smile. "A lot of girls know what it feels like to not have someone call you back or just fall off the face of the earth. So it was a cathartic slap for all of us."
Slapping Thor was a challenge, with Portman standing at a petite 1.6m and Hemsworth 30cm taller.
"There were secret boxes or ramps they would sneak in so I could be closer to him, otherwise there'd be no way I could hit his face. I'd be jumping and trying to reach his cheek," she said.
The actress was thrilled to return to her role. "It's rare to get the opportunity to play a female scientist in this kind of movie, so it's nice to have a foil for the superhero," she said.
"It was really, really fun for us to know that we were all joining forces again.
"These movies are pure entertainment, humour and action and everything you could want from an escape to the movies."
In the follow-up to the 2011 film, which was directed by Kenneth Branagh (Alan Taylor was in charge for this one), Jane has moved to London with her intern Darcy Lewis (Kat Dennings) to try to move on from her cross-realm romance with Thor, but she finds herself pulled into his world again by an ancient evil force.
Christopher Eccleston stars as Malekith the Accursed who, with his Dark Elves, is attempting to plunge the universe into darkness. So Thor teams up with Jane and Loki to try to save the day.
"Because Jane gets to go to Asgard this time, I was lucky enough to work with Tom [Hiddleston]," she said, even though it meant hitting him.
Playing Jane is a highlight in a career that includes roles in Michael Mann's thriller Heat, Woody Allen's Everyone Says I Love You, Padme Amidala in the Star Wars prequel trilogy and her Oscar-winning turn as committed ballet dancer Nina Sayers in Darren Aronofsky's Black Swan.
"Jane is such a multi-faceted woman. She has her career, but she also has time for romance. She's very serious about her work, but she has a lot of humour with her friends", Portman said.
"She's able to be both vulnerable and tough. You get to see a real woman, all the different sides come out."
As a style icon and face of Dior, Portman couldn't resist chuckling at her character's choice of clothes though.
"The funny part was combining the Asgardian robes with a Barbour jacket. I have my Earth Barbour jacket over the Asgard dress for much of the film, so the combination always makes people laugh," she said.
"It was definitely new to be in the Asgard clothes and, luckily, my character should feel uncomfortable in them, so any discomfort I had could be part of the character's feelings as well."
Despite the villainous threat posed by Malekith, there was a lot of humour on set.
"We all get along so well and we did a lot of laughing, maybe a bit too much laughing," she said. "It's just so fun to step on to a set where you already have friends. First day at work can feel like you're going into the dining hall at school, and thinking, 'which table shall I sit at?"'
Movie profile
Who: Natalie Portman
What: Thor - The Dark World
When: Opens at cinemas tomorrow
- AAP
