Prince Harry isn't going to have much time to work on his best man speech for brother Prince William.
The all-action royal is currently in Svalbard, Norway, training alongside a group of disabled servicemen who are attempting to walk unassisted to the North Pole.
Harry - who served for 77 days in the Afghan war – told journalists he had been "shown up" by the ultra-fit amputees but he was managing to "keep up".
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This week he is playing a full part in the team's intensive final preparations, which include sleeping out on the ice and dragging around a 220-lb sled while walking on special skis.
He will also be keeping an eye open for any polar bears, known to roam the area.
Then, on Friday, he will fly with them to the Polar Ice Cap to take part in the first five days of the 200-mile Arctic expedition.
Harry is working alongside four injured soldiers as patron of the Walking With The Wounded charity, which aims to raise £2 million to help other injured servicemen and women.
Asked if he was ready for the physically demanding challenge, the soldier-Prince admitted: "Not as ready as these guys are, but I'm just here to give them as much support as possible.
"I haven't had as much time to train. But today, to their huge amusement, they're going to see me on a pair of whatever they're called skis, this afternoon. So it should be entertaining for all of us."
With temperatures set to plummet to minus 40 on the trek, Harry will endure extreme conditions in one of the world's most inhospitable environments.
He hopes to "raise awareness of the debt that this country owes to those it sends off to fight."
"We must recognise their sacrifice, be thankful, so as far as we can ever repay them for it," he said.
Watch: Prince William takes George to meet his sister
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