In a case of True Blood versus blue blood, the Swedish actor will race Prince Harry's team in a 335km trek to the South Pole, which will test both their fitness and their determination. Dominic West, from The Wire, will also be joining the event.
Alexander, like Prince Harry, comes from a military background, having spent 15 months as a Swedish Marine. The actor, who is part of Team US, will compete against Prince Harry's Team Glenfiddich, and Dominic's Commonwealth Team.
The gruelling trial will be even more difficult, however, for some of the other team members — wounded service personnel who suffered physical or mental injuries in the line of duty.
"I'm honoured to be working and training alongside these soldiers to raise money and awareness for this very worthy cause," said Alexander.
"He is a great asset to the team and has bonded really well with all the other members during training," said team guide Inge Solheim, referring to the Swedish actor.
The challenge has been billed as "the largest modern-day expedition of its type", and will see the three teams spend four weeks trekking up to 20km a day in temperatures as low as -45°C. Biting 50mph winds and sleds weighing up to 70kg will add to the challenge.
The trek will no doubt be taxing but the charitable expedition will raise great awareness for Walking With The Wounded, and other charities involved including Soldier On and Soldiers to Summits.
Prince Harry confirmed his place in the race back in April, and has no doubt been training hard for the challenge. The teams will set out on 15th November.