Kristen Stewart (above) and Dakota Fanning both reckon Lady Gaga's the rockiest female star.

The two, who star in the 1970s rock biopic "The Runaways," say Lady Gaga's got the look.

"She's really hot," says Kristen. "She's got a look."

Dakota says the pink one is just, like, really cool.

"I am a fan of Lady Gaga because I think she's a really good singer and a really great entertainer and when you watch her perform, you know it's going to be a show. I think that's really cool."

But even though the two play killer female rock stars in "The Runaways," neither of them is ever going to be gracing a stage any time soon.

"I would never karaoke," says Kristen. "Every time I've even tried to do that, I've regretted it two lines in, and I end up talking [the lyrics]. It's making me embarrassed talking about it."

"I would never karaoke," says Dakota. "I am so scared. That is the scariest thing. Getting up in front of a room of strangers and singing songs — that is so scary to me."

You could have fooled me girls! In "Runaways," Kristen plays the real-life legends Joan Jett and Dakota plays Cherie Currie and they both belt out tunes.

"I was playing somebody else," says Dakota. "[Karaoke] is like you getting up and doing that."