Prince Harry has spent the night in a giant freezer to simulate the gruelling conditions he will face when he treks to the South Pole this winter.
The 29-year-old, who will race with a team of injured British servicemen and women against United States and Commonwealth groups, was subjected to ambient temperatures of minus 35C, with wind speeds of 45mph.
Harry, patron of the Walking With The Wounded charity, joked that it was a cold night's sleep.
When asked what was the worst part, he said: "Going in."
He spent around 20 hours in the cold chamber at Mira in Nuneaton where cars and military vehicles are put through their paces.
Alongside his four teammates - all of whom have amputated limbs after sustaining injuries in Afghanistan - Harry practised with the clothing he will wear on the 200-mile expedition and learned how to avoid frost-nip and frost-bite in the inhospitable climate in Antarctica.
After emerging from the huge testing facility, in which temperatures dropped to as low as minus 55C with wind-chill, the prince blew into his hands and rubbed them together to warm up as he chatted with his teammates over tea and biscuits.
Harry, who took part in the Walking With The Wounded trek to the North Pole in 2011 for five days, is patron of the Antarctica expedition.
He missed out on an attempt to conquer Mount Everest with the group last year because of his military commitments and he withdrew early from the successful North Pole expedition to attend his brother's wedding.
Harry shared a tent with Captain Ibrar Ali, 36, who lost his right arm in a roadside bomb blast in 2007, and Major Kate Philp, who chose to have her left leg amputated after her Warrior armoured vehicle struck an IED (improvised explosive device) in Musa Qala in Helmand Province in 2008.
Maj Philp, from Knightwick in Worcestershire, said Harry was a "good extra pair of hands" during the training exercise.
The 35-year-old Royal Artillery officer said having the prince with the team was "great".
"He's experienced at this, having spent some time at the North Pole also," she said.
"He knows what he's doing. He's got his military training, and it's very, very easy, so he's a good extra pair of hands."
Asked if Harry mucks in with the team, she said: "Oh God, absolutely. We wouldn't let it be any other way and he wouldn't want it to be any other way."
The team used bikes and cross-trainers to simulate the kind of exercise they will be doing during the race, before Mira engineers dropped the temperatures and turned up the wind.
Maj Philp said: "It was pretty cheeky, but it was fantastic training."
The teams then set up their tents, cooked food and bedded down for the night.
Oxford graduate Maj Philp, who still serves with 3 UK Division in Bulford, Wiltshire, said the team is bonding well.
She said: "It's great having Harry along, and hopefully he appreciates it too.
"It's a chance not just for him to experience all the practical stuff that we've just done as well, but for us to get together as a team and start to get to know each other better.
"It seemed very easy from the beginning, but it's certainly even more comfortable the more time we spend together."
The teams leave the UK in exactly two months' time, and Maj Philp said: "The reality is definitely dawning now, and certainly having experienced what we've just experienced here at Mira, it's really put it into sharp focus for us."