Hawaiian hottie Jason Momoa seriously bulked up to play the title character in this weekend's "Conan the Barbarian" -- putting on an impressive 20lbs for the role.
The once-lean Momoa, who also played barbaric on HBO's "Game of Thrones," reportedly went from 210lbs to 230lbs during training for the flick -- thanks to a daily routine of swordplay, 2 hours of weight lifting, cardio and a high protein diet.
Momoa isn't the first star to massively change his appearance for a role though, with celebs like Charlize Theron, Hugh Jackman, Jared Leto, Renee Zellweger and more packing on the pounds for a movie.
Some stars also drop the weight, like Natalie Portman and Christian Bale.
Check out the gallery above to see some shocking Before & Afters!