"There was no tequila! Not sure where that rumor came from, but it's false," she told PEOPLE at the AFI Fest 2010 presented by Audi Closing Night Gala Thursday. "I don't think we could have done that scene if we were intoxicated."
While "that scene" may not have required the aid of lime and salt, both Portman and Kunis (who are are close friends off-screen) say it wasn't the only hurdle overcome to make the film.
She adds: "They're never comfortable, same-sex, opposite-sex, it's never comfortable." Not to mention, both Portman and Kunis underwent rigorous ballet training and body transformations for the film.
"I started a year ahead of time," Portman, who claims she developed longer arms and better posture, says of her dance training, "and by the end I was doing eight hours a day."
Kunis says she "lost 20 lbs." and "looked like Gollum from Lord of the Rings! ... Everything was just protruding."