Wallabies coach Robbie Deans will on Thursday name his 23-man squad for the first Test against the British and Irish Lions in Brisbane on Saturday night.

Lealiifano is set to get his chance in the starting XV as one of five Brumbies in the squad.

ACT skipper Ben Mowen is also ready to make his Wallabies debut at blindside flanker while Stephen Moore and Ben Alexander will start in the front row and Pat McCabe is expected to be included on the bench.

Israel Folau, who has moved from league to Australian football to rugby, is expected to be on the wing with Berrick Barnes to resume at fullback.

Flyhalf has been the most contentious position with Deans opting for O'Connor and leaving mercurial Queensland No.10 Quade Cooper out of the Lions series.

Larkham led the Wallabies to a 2-1 series victory against the Lions in 2001 and was Australia's World Cup-winning flyhalf in 1999.

Despite Lealiifano playing in his first international match, Larkham said the 25-year-old was ready for the challenge and would give O'Connor confidence.

''The beauty with Christian is that he communicates so well and gives guys inside and outside him confidence,'' Larkham said.

''I can only see that as a positive for James' game. Christian offers a bit of an attacking philosophy with ball-playing at times compared to [McCabe at inside-centre].

''Over the last few years his experience, his communication, how calm and composed he is, the bits of brilliance in attack make him ready for this.''

Mowen has been rewarded for his role in helping rebuild the Brumbies from a Super Rugby rabble in 2011 to title contenders this season. He turned down lucrative offers overseas at the start of the year to recommit to the Brumbies until the end of 2015.

The main reason Mowen decided to stay was to chase his Wallabies dream and Larkham said: ''I haven't seen anyone apply themselves the way he has to get to this level.''

Brumbies coach Jake White said the duo's rise and a five-strong ACT contingent was reward for the Brumbies' stellar season, in which they have won a Super Rugby finals berth for the first time since 2004.

''If those guys are in there, it's fantastic. It's a wonderful achievement and great for our club, it highlights what the Brumbies have achieved. It means the program is working,'' White said.

The Waratahs' Kane Douglas will partner captain James Horwill in the second row.