Kristen Stewart couldn't put all her effort into a kissing scene for her latest movie The Runaways as the person on the other end of her lips was a minor.

Dakota Fanning was just 15-years-old at the time the pair filmed the movie, and Kristen revealed she wasn't allowed to “grope” the teenager whilst filming a kissing scene.

KStew told Access Hollywood that she couldn't touch her BFF, Dakota, at all during the scene.

"She was 15, and I wasn't allowed to grope her.

“I'm actually not kidding, there are major restrictions that I don't remember from when I was younger."

Before you get too hot under the collar, Kristen added that the kiss wasn't “a big deal”

"I don't want to give anything way. It's a really passionate, hardcore scene. No, it's just a kiss. It's not really a big deal.”

The film tells the story of the formation of the '70's girl group The Runaways, and the kiss is part of the relationship between Joan Jett (played by Kristen) and Cherie Currie (played by Dakota).

Will you be going to see Kristen's latest film or are you all about Eclipse after today's trailer?! Tell us on Twitter...

Kristen's star style...