He's the qualified electrician who works at a mine and wants to move to Australia.

He's a world away from Canberra and the freezing winter gripping the capital.

But Viljoen's Brumbies passion started well before coach Jake White ignited a South African connection in the capital.

The 25-year-old has been on board for 15 years supporting the enemy and copping it from his countrymen for backing the visitors.

The Brumbies will play the Pretoria Bulls in the Super Rugby semi final at Loftus Versfeld on Sunday morning Australian time with the winner advancing to the championship match.

And while most Brumbies fans will stay up late in Canberra, Viljoen will be fighting a one-man crusade in the stands in Pretoria.

"Yeah, we'll be the only two people in the crowd wearing Brumbies jerseys [in Pretoria]," Viljoen said.

"South Africans obviously describe me as a traitor, a person without patriotism or integrity.

"But I feel that every guy has a choice to support whoever they want. I expect some cheeky comments ... but I've learned to live with it.

Viljoen started supporting the Brumbies in 1998.

As a budding flyhalf, Viljoen was swept up in the play of club greats George Gregan and Stephen Larkham.

Earlier this year he flew 1400 kilometres and drove 500 kilometres more just to watch the Brumbies play the Stormers in Cape Town.

In his cupboard he has a collection of almost every Brumbies jersey ever worn. He's got signatures from some of the greats, pictures with the team and an undeniable rugby passion for the Brumbies.

When the Brumbies tour the Republic, he tries to get to Bloemfontein and Pretoria just to get a glimpse of his favourite team.

"Being a Brumbies supporter in South Africa is very difficult ... over the years I've encountered a few incidents," he said.

"But I'm still standing proudly behind my team.

"It's definitely worth it - I feel that if you commit to a team, you stick with them through the highs and lows.

"And my biggest dream is to go and watch the guys play in Canberra."