New Wallabies attack mentor Larkham and 11 Brumbies will join Test coach Michael Cheika and 40 other players from around Australia at the planning camp in Brisbane.

It's the first major camp of Cheika's tenure as he calls in World Cup hopefuls in an attempt to fast-track his plans for the team at the end of the year, but the cost is Larkham and Brumbies missing Super Rugby training on Monday and Tuesday.

But before Larkham officially starts his first Wallabies job, the World Cup-winning five-eighth will play for the Australian Defence Force Old Boys against the Silver Foxes in a charity match on Saturday before flying to Brisbane.

"In my career with the Wallabies we didn't do anything like this. I think it's a great idea and it's something that's needed," Larkham said.

"Obviously you don't want it to detract from a Super Rugby campaign and distract players throughout a campaign, but it's very difficult to come together at the end of a year and click straight away.

"You've got to get on the same page as quick as possible and this is a good way of doing it. Brumbies-wise, we'll adjust our training week and I'll work with the guys in Brisbane.

"It will be slightly modified, but we'll still get a good result out of it. As far as I'm aware, this is the one Wallabies get together with everyone."

Larkham will go head-to-head with some of his former Wallabies and Brumbies teammates in a match at Bungendore.

Owen Finegan has already put a target on Larkham's chest and will be trying to grab his Super Rugby and World Cup-winning teammate at every opportunity.

Finegan is vice captain of the Silver Foxes team, which also boasts Canberra Raiders great Brad Clyde, Joe Roff, Al Baxter, David Croft, Dan Vickerman Richard Harry, Julian Huxley, Pat Howard and John Langford.

"[Larkham] has no chance of getting me. I'll get him somehow, whether it's before, during or after the game," Finegan said. "He said that if I'm running for the tryline, he won't be standing in front of me. Most of the forwards still like rumbling and ripping into it.

"It's more for fun than trying to win a Test match. But everyone likes to test themselves and see how they're going, I'm lucky I've played for the Silver Foxes and Gungahlin over the past few years."

Larkham retired from playing in 2011 to start a coaching job with the Brumbies.

He almost made a comeback to answer an SOS at the Brumbies in 2012 when Matt Toomua and Christian Lealiifano suffered season-ending injuries.

But now his playing time is limited to slotting into training sessions as the opposition to prepare the Brumbies in his first year as a Super Rugby head coach.

"Those guys [the Silver Foxes] on the other side will still be very fit and keen to hurt people," Larkham said. "I doubt [Finegan] will get a hold of me, but I'll definitely be trying to cheap shot him.

"The white-line fever takes over, it gets very serious. Particularly with old has-beens who have played for the Wallabies, they've still got a point to prove.

"If you go in half-hearted, you get an injury. So it's best to go in as hard as you can and expect to get hurt."

The Silver Foxes have raised more than $250,000 for the Black Dog Institute to assist with the diagnosis, treatment and prevention of depression.

SILVER FOXES MATCH

Saturday: Silver Foxes v ADF Old Boys at Mick Sherd Oval, Bungendore, 3pm. Donations to the Black Dog Institute can be made here.