's goodbye kiss will have to last Cressida Bonas
for five weeks as he treks across Antarctica
to raise awareness for wounded soldiers.
The prince, 29, heads for Cape Town, South Africa, on Sunday to take part in Walking with the Wounded
's South Pole Allied Challenge – a race that spans over 200 miles in temperatures that can dip to 50 degrees below zero. The competition will involve three seven-man teams from the U.K., the U.S., Australia and Canada. During that time, none of the participants will be calling home.
"He won't get to speak to his girlfriend for about four weeks, which is tough, but it's the same for everyone," Walking with the Wounded's cofounder Ed Parker tells PEOPLE. "There's no airs and graces. He's a soldier, he really gets who we are and what we are trying to do, and we're lucky to have him on board, especially for the whole five weeks."
During a farewell event in Trafalgar Square on Thursday, Harry unveiled the trophy that will go to the winning team and praised the wounded soldiers who will be accompanying him on the long journey. "All the men and women have achieved so much just to get here, let alone actually walk to the South Pole. It's just a wonderful display of courage on their part," he said.
, who plays Eric Northman on True Blood
, will also take part in the race and said he plans to beat his royal rival
"I'm pretty stubborn and motivated and I don't give up easily," Skarsgard, 37, tells PEOPLE
. "It's going to be an honor to meet [the prince]," he added.
Each of the three teams – Prince Harry's Team Glenfiddich (U.K.), Alexander Skarsgard's team Noom Coach (U.S.) and Dominic West's Team Soldier On (Australia and Canada) – will include four wounded servicemen and women and pull sleds that weigh over 150 lbs.
With just days before their departure, Parker said Harry "has the same concerns as everyone else, but he's a fit young man and he clicks with the team, which is so important. He's a really good guy and great fun to have with us."
Parker added that Harry has been put on a strict exercise regimen to prepare for the monthlong trip, and he won't be getting any VIP treatment.
This is the second expedition Harry has been on with the charity, having trekked to the North Pole in 2011 for five days. Walking with the Wounded helps retrain injured military personnel for careers in civilian society.