See Kristen Stewart Flex Her Muscles!

Looks like Taylor Lautner isn't the only one who got buff for "New Moon."

See photos of Twilight stars as kids!

Kristen Stewart flexes her muscles during a one-on-one interview with "Extra's" Mario Lopez. Watch the raw, behind-the-scenes footage from "Extra's" Samsung Jack phone below.

Kristen Stewart Flexing

Check out more photos and footage of the "New Moon" cast -- and send "Extra" your red carpet questions!

Lopez asks the "Twilight" star if he could play one of the werewolves in the vampire saga (out Nov. 20).

Stewart's response? He's "got the guns!"