Harry, who celebrated his birthday on Sunday, spent Monday night in a subzero training chamber, battling temperatures as low as 49 degrees below zero to train for a trip to the South Pole.
The prince will travel to the Antarctic in November to compete against teams from the U.S. and the Commonwealth in a 16-day race across the South Pole. Harry will join a team of injured British servicemen and women to raise funds for Walking With the Wounded, a charity he patrons that provides rehabilitation services for military veterans.
Harry spent 20 hours in the cold chamber alongside his four teammates, each of whom had limbs amputated after being injured in Afghanistan, according to the U.K.'s Guardian.
The prince's dip into the cold is not the first time the thrill-seeking royal has put himself in freezing temperatures. In 2011, Harry took part in the Walking with the Wounded trek to the North Pole for five days where he spent the night in a tent while temperatures outside dipped to a chilly negative 25 degrees.
"Is that all it was, minus 25?," Harry joked at the time to ABC News' Bob Woodruff. "[It] felt a lot colder than that in there."
"[It] just proves that, no matter what, you can progress with your life," he said of his teammates. "You can do things beyond any imagination that you ever thought was possible."
In this year's race, Harry will face off against "True Blood" star Alexander Skarsgard, who will head the U.S. team, and "The Wire" star Dominic West, who will race with the Commonwealth team.