Gerard Butler nearly drowned when a 20 foot wave broke on his head whilst filming a scene at Mavericks, California.
Gerard Butler was a very inexperienced surfer before taking on his role in the film. Jonny Weston, on the other hand, had been surfing for about 10 years.
Gerard Butler was briefly hospitalized when a surfing stunt went wrong. Part of his recovery involved a heavy course of painkillers. Butler would later check himself into the Betty Ford Clinic to wean himself off these painkillers.
Jonny Weston was hired with no prior film or commercial acting work. He was discovered via an audition video he submitted via a casting website where anyone who's looking for modeling or acting work can sign up for, create a profile and audition for work.