Isla Fisher nearly drowned on the set of her new movie 'Now You See Me' after getting trapped while doing a stunt in a water tank.The 37-year-old Australian star - who has two daughters, Olive, five, and Elula, two, with her comedian husband Sacha Baron Cohen - was left struggling for air when she got tangled up in chains while performing a stunt as a glamorous escapologist in a water tank, after being submerged for two and a half minutes.The actress told the MailOnline website: "They had a guy who was off camera, but he was a long way away with a can of oxygen. By the time I realised I couldn't get up and beckoned for him, I realised that I had run out of air."The petite star explained that there was an emergency "kill switch" in the tank, which would have completely drained it in 70 seconds but she couldn't reach it.She said: "Luckily, I managed to get free and stay level-headed and got out before it went even more horribly wrong."Isla revealed all she could think about was what she was wearing in that scary moment.She said: "Not in a swimming costume. No one wants to go in a swimming costume."Despite coming out of the incident unscathed, the actress doesn't think she is brave in front of the camera.She said: "I don't see myself as particularly brave. I rely on gut instinct to, accept a role. If something terrifies me I am going to do it."The director (Louis Leterrier) said to me, 'Wow. I've worked with so many actors on big action movies, and you're the only one who's done all their own stunts'."I said, 'I didn't know I had a choice'. I thought you just had to get on with it. It's the Australian way."I'm willing to pull a bad face, and to sweat a bit."