Isla Fisher spoke out after almost drowning in movie stunt that nearly went terribly wrong

Isla Fisher revealed that she almost drowned while filming a high-stakes movie stunt for Now You See Me.

The Australian actress, 48, almost didn't make it out alive of one scene in the 2013 flick which saw her pull off a Houdini-esque escape from an underwater tank.

Incredibly, the production crew didn't realise that she was slowly suffocating in the water - as they just thought she was just putting on an A* performance. Take a look at the scene for yourself here:

As you can see, Fisher - who announced her split from Sacha Baron Cohen in April - found herself in quite the pickle in the opening scene of Now You See Me, which introduced us to 'The Four Horsemen'.

It begins with Daniel Atlas (Jesse Eisenberg) showing off a mind-blowing card trick, while Merritt McKinney (Woody Harrelson) is seen flaunting his hypnotic abilities.

Jack Wilder (Dave Franco) then performs a stunning illusion with a spoon, before Henley Reeves (Fisher) makes her first appearance shackled underwater with piranhas hovering above.

The glamorous escapologist enters the room to an awaiting crowd of adoring fans, explaining she has just one minute to escape her shackles before the terrifying fish fall into the tank.

Although risky stunts such as this are typically performed by professionals, Fisher wanted to do it herself.

Isla Fisher almost drowned while filming the high-stakes stunt for Now You See Me (Frazer Harrison/Getty Images)

"I don't see myself as particularly brave," she told Cosmopolitan in 2013. "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'll bet she was kicking herself for making that call when things went awry during filming, though.

In the scene, Fisher's character manages to free herself from the shackles before realising that her chains are trapped between the grates at the bottom of the tank.

So the Confessions of a Shopaholic star is meant to look quite distressed at this point - however, she didn't have to act out this emotion, as she really was fearing for her life at that moment.

While the mother-of-three was shooting the scene underwater for two-and-a-half minutes, her chains actually became trapped for real.

She started frantically banging on the walls of the tank to alert the crew, but they thought she was acting.

Fisher recalled: "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 actress became trapped underwater for real when her chains became stuck (Lionsgate)

In another interview, she explained that she had spent two months preparing for the scene, which ultimately took three days to film.

"I was just practicing holding my breath and getting comfortable with the handcuffs," she explained. "It still didn't stop me from being actually stuck underwater.

"I couldn't breathe or get up for air, which was a little hairy," she said. "A lot of the time I was in the tank, it was just like white noise. I couldn't hear anyone."

She explained that she was just about able to decipher what one of the movie's extras was mouthing to her, while being hyper-aware that the clock was ticking.

"The adrenaline of being chained underwater meant that I had less oxygen in my lungs, I ran out of air quicker and panicked slightly more," Fisher said.

"I got up to three minutes underwater - that's what Louis, the director, told me he saw when he was in the editing room. It was terrifying, but I really enjoyed it."

"It was terrifying, but I really enjoyed it" (Lionsgate)

Talk about a hard day at work.

Fisher explained she was unable to reach a safety button, or 'kill switch', which would have expelled the thousands of gallons of water from the tank in 70 seconds.

"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," she went on.

"Luckily, I managed to get free and stay level-headed and got out before it went even more horribly wrong.'"

She also revealed that there was only one thing on her mind throughout her near-death experience - the prospect of passing away while wearing sequined swimwear.

"Not in a swimming costume," she added. "No one wants to go in a swimming costume.''