TV viewers will see dramatic moments as Prince Harry suffered a health scare while trekking across the frozen wastes during his South Pole challenge.
Harry was left weakened and in pain after being laid low with crippling altitude sickness and exhaustion which forced him to rest for 36 hours while journeying across the Antarctic plateau on foot.
His problems during the challenge, which took place in December, have emerged as scenes featuring his health woes are to be screened during an ITV documentary about the polar adventure.
In the second episode of Harry's South Pole Heroes, to be screened on March 23, he admits: "Antarctica jumped up and bit me on the a**."
Harry undertook the journey dragging his sledge of supplies more than 124 miles (200km) over the snow and ice, alongside 12 servicemen and women from the UK as well as teams from other nations in the Walking With The Wounded expedition.
But the exertion and the high altitude, as well as dehydration combined to leave him drained. During the eighth day, after a nagging headache, he tells a medic: "It feels as though it's expanding. It's getting worse and worse."
He is seen being tested to check he still has feeling in his limbs and asked about whether he has vomited as a result of his condition.
Harry explains later: "If you show a weakness to Antarctica, I think it exploits it. And I think it will slowly grind you down until you have the utmost respect for it, which I now have.
"I thought I could come out here and just crack on and see it through without any issues, make sure I'm here for the guys when they need me.
"I'm frustrated and disappointed in myself, but it really does prove how physically and mentally tough these guys are," he said of his fellow adventurers, some of whom had lost limbs or suffered other injuries during service in Afghanistan.
In order to relieve his symptoms he was ordered to rest for 36 hours, which added further frustrations.
" Being tent-bound really sucks. I don't really enjoy sitting around and doing nothing, especially when I know they're walking 17km.
Foul weather conditions, with temperatures plummeting as low as minus 40C (minus 40F) eventually led to the competitive race element of the challenge being abandoned, with the teams eventually arriving at the South Pole together on skis.
Relieved Harry said of his team at the finish: "I'm so happy for them. They've done so well - every single person, but especially these guys and girls. I'm honoured and privileged to be here with these guys. It's been very special."
:: Harry's South Pole Heroes Episode 2 is screened at 8pm on March 23 by ITV.