Helen George was taken aback to find she'd genuinely be swimming with sharks on Shark! Celebrity Infested Waters. The star of Call the Midwife is among the celebrities set to encounter marine life, culminating in a dive with tiger sharks.

Despite her shark phobia and fear of submerging her head underwater, Helen joined the show under the impression that she wouldn't have to face the challenges because "it's TV" and "who would actually do that?" Speaking to Radio Times magazine, she confessed: "I'm quite gung-ho as a person, so I thought I'd be fine, but I genuinely wasn't. At that point, the sharks were small fry. It was more about the water!"

The 41-year-old signed up for the challenge thinking of her children with ex-partner Jack Ashton, Wren, seven, and three-year-old Lark.

She explained: "I wanted to get more confident for them. They were impressed I even went in the first place, because they didn't think I would. I was really terrified of the water, so I might be a bit embarrassed about some of the scenes!"

"I'm an actress and I play other people's vulnerabilities, so playing my own is always terrifying. I'm ugly crying, there's no hair and make-up... it's not glamorous. Now I'm thinking, 'What have I done?' I haven't been 'myself' on screen since I did Strictly [in 2015], and that was uncomfortable for me."

Helen's trepidation put her training behind peers like Lucy Punch, Sir Lenny Henry, Ross Noble, Ade Adepitan, and Dougie Poynter, and at one stage, she doubted her ability to participate as she feared failing her PADI (Professional Association of Diving Instructors) qualification.

She confessed: "They didn't know whether I'd be able to pass my PADI in time for filming, because I wasn't up to the standard that everybody else was, because I was really scared. I thought they were gonna put me on the next plane home and get someone else."

However, she turned down the alternative of taking a snorkelling course. She elaborated: "It would have meant I was separate from the group and I didn't want to be, so I knuckled down, put my big girl pants on and got on with it! I thought, 'I'm not going to be behind everyone else. I'm not going to let myself fail in week one."

In one clip, she's targeted by a stingray and says: "Jesus Christ, it's coming right at my vagina! It's there. It gave me a tickle. I've never been tickled by a stingray before ... it was actually quite pleasant."

Shark! Celebrity Infested Waters airs on Monday, July 14 at 9pm on ITV.