Jessica Alba (Into the Blue, 2005)

Jessica Alba and Paul Walker hold their breath underwater in Into the Blue. Sony

Jessica Alba took up free diving when she worked on the late ’90s TV show The New Adventures of Flipper, and carried her experience over to Into the Blue, a heist thriller in which she co-starred with the late Paul Walker.

“Free diving is like an extreme sports version of snorkeling,” she told CBS News in 2005. “That’s about 50 feet deep. And basically what you do is you hold your breath and you wear a weight belt and go down as fast as possible and hold your breath for minutes at a time. ”

Alba said she and her fellow actors would compete at it: “I think I had the longest breath-hold. It was like one minute, 20 seconds,” she said.