FINTASTIC TELLY

Throughout the series, the celebrities dive with various species and take on fear-inducing challenges, all while learning firsthand about the critical role sharks play in maintaining ocean health.

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bull sharks, and the formidable tiger shark.

"I am quite scared of swimming and I started to think, is this a good idea? Let alone the sharks," says Helen, 41.

"But I really wanted to push myself. It sounded like such an interesting thing to be part of - something I knew nothing about - and with an amazing group around me. So it just felt like a no-brainer."

Countdown star Rachel, 39, sheds light on the strict safety protocols in place during the dives, which grew more intense as the sharks got larger - and more dangerous.

"We had safety divers all around us," she reveals. "But when you're in the water with these enormous, completely wild animals, you don't really know what's going to happen.

"We were building up to dive with the tiger sharks, which are one of the 'big three.' After the tiger shark, the next biggest, potentially dangerous shark is the great white.