They became fast friends on the set of “The Runaways,” and recently Dakota Fanning revealed how she and Kristen Stewart became so close.

The young actress admitted to Access Hollywood that she and Stewart share a steamy kiss in the Joan Jett biopic due out next year.

Of the intimate moment, the Fanning says, “It was passionate. We’re playing Joan Jett and Cherie Curie and they’re best friends in the film and became really close in real life. And that’s something that went down back in the ‘70s.”

She continued, “We were so into the scene and into the script and the characters.”

In other news, the two actresses also star opposite each in “New Moon” which hits theatres this Friday, November 20th.