Rachel Riley admits leaving will amid fears of being a 'goner' during Countdown absence

Rachel Riley feared the worst as the Channel 4 favourite took part in a brand new series which would scare most of the public. The mum-of-two joined seven celebrities for Shark! Celebrity Infested Waters - a new reality show where they came face-to-face with underwater sea creatures. The 39-year-old opened up about her experience with sharks which forced her to make a will. Rachel admitted she was frightened before she even flew out to film the show. Rachel says she expected a nice gentle start, but on the first day she and the others were told to put on a wetsuit and scuba gear and get ready to dive. She then had to climb down a ladder into deep water with nothing but a heavy-duty metal cage between her and the killers about to approach.

"I did feel fear at seeing a shark up close for the first time, my heart was racing but I didn't freak out," Rachel told the Daily Mail. "We later learned that every kind of shark has a different personality. The bull shark is a sneaky f*****. The experts don't trust them." She continued: "You can see their eyes. You can sense their movements. And you're in their world."

The mathematician, who also is a regular on Countdown and its late-night spin-off Eight Out Of Ten Cats admits she was afraid before even getting on the plane.

"I wrote my will before we went," Rachel remarked. "This trip made me want to make sure everything was signed, just in case. They're wild animals. You're scuba diving. Anything could happen."

The on-screen star recalled a trip with her husband Pasha Kovalev while swimming in the Galapagos islands and spotted a "bright pink thing in the water".

She told the publication: "We thought it was a discarded life jacket. It was a sea lion that had just been bitten in half by a bull shark, and it was trying to crawl out of the water."

ITV's latest reality series, Shark! Celebrity Infested Waters will officially debut at 9pm on Monday 14th July on ITV1.

The line-up for the series will feature seven celebrities, including Helen George, Lucy Punch, Sir Lenny Henry, Ross Noble, Rachel Riley, Ade Adepitan and Dougie Poynter.

The series will see them all on the island of Bimini in the Bahamas, which is home to seven to 10 different breeds of shark.

Throughout the episodes they will be challenged to dive with shark breeds of increasing size and danger.

Meanwhile, Rachel, who has been on the show since 2009, returned to her Countdown duties after taking a short break earlier this year.

She confirmed the news on her Instagram at the time, writing: "Best of luck to @tomrocksmaths for the next few weeks on Countdown!" the presenter wrote beneath a post.

It continued: "Dr Tom will be keeping my numbers warm from Monday for the next 3 weeks whilst I'm away. I had a good excuse, I'll tell you more soon."