All emerging scrumhalf Ryan Lonergan can do is shake his head. But that's Kuenzle, the light-hearted character he teamed with for the Junior Wallabies on the world stage two years ago.

The same playmaker who shows no signs of nerves ahead of a Super Rugby AU blockbuster against the NSW Waratahs at Canberra Stadium on Saturday night.

The 22-year-old who walks around the club's University of Canberra base and clips people over the back of the head for a laugh.

"Not just his really close friends, he does it to everyone. He's just got terrible chat mate, you've really got to witness it to understand it," Lonergan laughed.

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"He's very annoying actually. I'm sure everyone would agree with that, he's a child, he's much like Mack Hansen actually, very annoying."

But Lonergan says every club needs a Kuenzle or a Hansen - especially when you are preparing to meet your bitter rivals with so much at stake.

The Brumbies sit on top of the ladder and a win could see them get a foot in the door of a home final. Lose, and they could drop as low as third but still with a game in hand.

"It can all get really serious, and sometimes too serious," Lonergan said.

"At the end of the day we're just playing a game, it's what we love and what we grew up doing. If you stop seeing it as a fun thing to do with your mates, then you're not going to perform at your best. Having people like that who can lighten the mood, it's good."

It was much the same when the Brumbies duo first joined forces for Australia at the World Rugby under 20s championship in France two years ago.

Look back now and it's a wonder they finished no higher than fifth - the squad boasted names like Lonergan, Kuenzle, Hansen, Fraser McReight, Jordan Petaia, Len Ikitau and Tom Ross. Only injury kept Rob Valetini away.

"I remember playing alongside BK, he's really good to be inside," Lonergan said.

"He's really calm and collected, I'm expecting the same. It might look like a whole bunch of new combinations but we train full-time together so everyone knows how everyone is going to play."

Lonergan will make the second start of his Super Rugby career this weekend, making for a stark contrast with the half sitting on the bench.

Wallabies scrumhalf Nic White is set to play his first match in Brumbies colours since 2015 after coach Dan McKellar's squad reshuffle made for 16 changes across the match day 23.

Yet the Brumbies mentor doesn't look at it as a raft of changes including nine to the starting XV. This is just a team he believes is capable of beating the Waratahs, and he is banking on two youngsters to steer them around.

"Lonners was outstanding for us at the start of the year and would have featured more if he didn't pick up that ankle injury," McKellar said.

"BK has had some really good experiences over the past month, some good passages in those games and some good learning as well. It's an exciting team."

So it is fitting the Brumbies will be led around the park by two faces expected to help usher in the next generation.

"There's always something a little different about facing the Waratahs, we really don't like them down here," Lonergan said.

"There is something different about the week but we've just got to be able to control our emotions and play the type of game we want to play, even though it is a bigger occasion than most.

"Ever since I have played footy here in ACT, we've never really liked the Sydney teams and it's the same all the way up."

Didn't Kuenzle come through those same systems you say you don't like? Lonergan breaks into a smile. "He did, and it shows."

SUPER RUGBY AU ROUND EIGHT

Saturday: ACT Brumbies v NSW Waratahs at Canberra Stadium, 7.15pm.

Brumbies squad: 1. James Slipper, 2. Connal McInerney, 3. Allan Alaalatoa (c), 4. Murray Douglas, 5. Cadeyrn Neville, 6. Lachlan McCaffrey, 7. Will Miller, 8. Pete Samu, 9. Ryan Lonergan, 10. Bayley Kuenzle, 11. Tom Wright, 12. Irae Simone, 13. Solomone Kata, 14. Andy Muirhead, 15. Tom Banks. Replacements: 16. Lachlan Lonergan, 17. Scott Sio, 18. Tom Ross, 19. Darcy Swain, 20. Rob Valetini, 21. Tom Cusack, 22. Nic White, 23. Len Ikitau.

Waratahs squad: 1. Tom Robertson, 2. Tom Horton, 3. Harry Johnson-Holmes, 4. Ned Hanigan, 5. Rob Simmons (c), 6. Lachie Swinton, 7. Michael Hooper, 8. Jack Dempsey, 9. Jake Gordon, 10. Will Harrison, 11. Alex Newsome, 12. Karmichael Hunt, 13. Joey Walton, 14. James Ramm, 15. Jack Maddocks. Replacements: 16. Robbie Abel, 17. Angus Bell, 18. Te Tera Faulkner, 19. Tom Staniforth, 20. Hugh Sinclair, 21. Mitch Short, 22. Ben Donaldson, 23. Lalakai Foketi.