Wallaby skipper George Gregan will this weekend become the world most capped scrum-hlaf, surpassing Springbok Joost van der Westhuizen's total of 77 caps.

"Joost was such a great player so it's certainly an honour to surpass a record like his," said Gregan.

Gregan will be playing his 78th Test wearing the No.9 jersey, overtaking former Springboks supremo Joost van der Westhuizen who has 79 Test caps, but played two of those matches on the wing.

Zambian-born Gregan started Test rugby back in 1994 as he means to finish it - with style.

In an unforgettable debut season he saved the Bledisloe Cup for Australia with his diving tackle on tryline-bound All Black Jeff Wilson. He's hardly missed a match since, and his freakish consistency has put him a class above any other halfback.

With a history of occasional on-field verbal flare-ups, there were question marks over his suitability for the role of Australian captain following John Eales' retirement last year. But typically he has made the role his own, toning down his on-field rhetoric while his decision-making remains exemplary.

"Playing rugby you've got to have a different mentality," Gregan said. "It's a physical game, its confrontational and certain positions require certain traits and mine's one where you communicate a lot, you talk a lot and that's just part of your job.

"But when I'm off the field, I'm not playing rugby, it's a different scenario and I don't have to behave that way so I don't."

Gregan says he got his best grounding in rugby by watching Ricky Stuart lead their school side St Edmunds in Canberra.

"He (Stuart) was awesome, he had the biggest influence on me by a long way," says Gregan. "He was a very good communicator and a very hands-on kind of player. He was the best by a mile so I thought he's got to be doing something right."

Gregan continued to watch Stuart when he started his league career with the Canberra Raiders and felt he reinvented the way halfbacks played that game.

They remain close friends, although between rugby, work and family, which includes wife Erica, son Max and a new baby in November, there isn't too much time for socialising.

The Wallabies have only won once at high altitude Ellis Park, back in 1963. They have only really won once convincingly - 26-3 in Cape Town - on South African soil back in 1992, which was the Springboks' first year back in world rugby.

If everything goes their way on Saturday - a win by at least 25 points and a bonus point for four tries - the Wallabies will secure a record third successive Tri-Nations title.

"You don't think about it too much, we're focused on playing our best 80 minutes so far this year and if we can do that we know that we'll get a really good result and if we do that we'll create history.

"Its amazing how one feeds off the other but you've just got to focus on what you can control and that's our own performance. You don't think about it too much now but later in your career when you retire you can think about what a great time it was and what a wonderful achievement it was."