Ronan Keating and pals battle jellyfish in charity swim
Five celebrities have told of their battles with giant jellyfish while swimming the Irish Sea in a marathon fundraising effort.
The charity relay for Cancer Research UK sees the famous names, led by boyband idol Ronan Keating, swim the 56 nautical miles (65 land miles) from Holyhead in Anglesey, North Wales, to Dublin.
Keating, 34, was first off the slipway in his wet suit and flippers at around 9pm last night, followed by TV presenter Jenny Frost, who then handed over to Strictly star Pamela Stephenson.
Gadget Show host Jason Bradbury and Olympic medallist swimmer Steve Parry are also taking part.
The team is following the sea's tidal pattern and currently heading north after swimming for about 21 nautical miles in a south westerly direction.
At the near-centre of the waters, Mount Snowdon - the highest peak in England and Wales - was just a distant spot on the landscape behind them.
Ahead in the far distance were the peaks of County Wicklow about 34 miles away.
The sea at this point is around 151 metres deep.
Speaking during a break, Keating said he was mostly spending his hour-long stints swallowing sea water and avoiding "alien-like" jellyfish.
"I'm not one of the advanced swimmers so I'm concentrating on my swimming, my breathing and keeping my body moving," he added.
"We were warned about the Lion's Mane jellyfish but there are hundreds and it's frightening when they are right there sitting in front of you.
"You gasp and lose your breath but you've just got to keep moving.
"Thank God we haven't seen any sharks, I'm very happy about that."
Tidal variations mean the swimmers have to zig-zag across the waters and could end up covering a distance of up to 70 nautical miles (81 land miles).
Keating added: "We're pretty much half way across the Irish Sea now.
"It's an amazing feeling to think at 9 o'clock last night we were in Holyhead, it was so daunting.
"It was so crazy in Holyhead, so many people and cameras flashing.
"I've never been in the sea at night time before, and stepping into the cold water, it took me a minute to catch my breath.
"I was thinking, 'okay, you have to swim now, get your head down and start going'.
"I was a little panicky, but kind of emotional too.
"I just had to dive in and it was incredible.
"We've talked about it for 12 months but it was finally happening, it was an incredible moment."
The celebrities are being helped by five 'super swimmers' and while at sea each member of the relay is expected to swim for one hour until arriving in Dublin after an estimated 40 hours.
Keating came up with the idea with Sir Richard Branson, who was also due to take part in the relay but pulled out at the weekend after his Caribbean home on Necker Island burned to the ground.
They hope to raise over £1 million for Cancer Research.
All the celebrity swimmers taking part have loved ones who have had cancer.
Keating, Frost and Stephenson lost their mothers to the disease and Bradbury's brother was diagnosed with skin cancer earlier this year.
Parry, 34, found out he had testicular cancer 18 months ago, three weeks after getting married.
He did his first swim at around 3.30am today.
"It seemed like it was going to be the graveyard shift but it was so nice," he said.
"Once you get over the cold and the darkness - the pitch black - it's a beautiful environment to be swimming in."
Parry, who won an Olympic bronze in 2008, said it was more of a mental challenge than a physical test.
"Your mind starts to play tricks," he said.
"You worry about sharks, or jellyfish surrounding you or the canoeist moving away."
Temperatures in the sea over the next few days are expected to be a "mild" 12-14C, a spokeswoman for Meteogroup, the weather division of the Press Association, said.
A band of high pressure over the area should also lessen wind speeds and help calm the waves on the notoriously choppy stretch of water.
At least 30 species of shark are known to pass through the Irish Sea, including the enormous basking shark, the world's second largest fish.
But it's the Lion's Mane, the world's largest species of jellyfish, which has been providing the closest encounters for the swimmers.
Gadget guru Bradbury, 42, told how he was stung in the nose by one of the creatures.
"It hit me and it was like being slapped in the face with some force," he said.
"It stung me, went right down the right hand side of my leg, caught my ankle and went off.
"It really made me jump.
"I panicked and stopped, my heart was thumping and I was gasping for breath.
"The canoeist shouted to keep on going and that's what I had to do."
Six hours later, he said his nose was still "pulsating" but he is being treated with skin cream and pain killers.
Frost, 33, said: "I went in at about 7am and it was lovely in the water but there were lots of jellyfish so it was quite scary.
"They are huge, like a cross between a nuclear bomb and aliens.
"They are ugly, scary things with huge, long tentacles.
"When you come face to face with one, you just feel so vulnerable and so minuscule.
"It's quite a humbling experience."
Stephenson, a clinical psychologist and the oldest member of the group, described her second swim as "fabulous".
After a stint in the harbour last night the 61-year-old jumped into the sea for a second time at around 8.30am today.
She said: "I had a bad time when I was in the harbour because there were so many lights and I got disoriented.
"But when I got back in for my second swim, it just felt like me and the sea and the kayak and I had a lovely time. It was so quiet.
"I saw the jellyfish right away and it worried me because some of them were swimming upside down and the tentacles were floating up towards me.
"I thought I was going to get tied up in these milky, transparent creatures.
"It was horrible. I must have counted over 100 of them."
The team is expected to land in Dublin at around 6.30am tomorrow.
To follow the progress of the swim, visit www.the-swim.co.uk.