It's grueling work filming the "Twilight" films back-to-back, but the stars of the flick have at least one stress outlet -- playing music.
In Saturday Night Magazine, Nikki Reed (left) -- who plays Rosalie Hale -- says the stars are in fight training "all the time" and that "there were weeks when I would work Monday through Sunday" ... but it ain't all hard work. (Watch new "Eclipse" clip.)
Co-star Jackson Rathbone (right) -- who plays Jasper Hale -- dished on the makeshift band the cast put together, saying "we'd all get together inthe rooms and we'd have jam sessions and make up songs. I'd play guitarand harmonica, Rob [Pattinson] would play guitar and sing or Kristen [Stewart] would playguitar."
Both will appear in "Twilight: Eclipse" -- opening June 30.
