Stephen Moore and Matt Giteau will become the newest Wallabies centurions against Scotland in Sunday’s Rugby World Cup quarter-final at Twickenham.
David Pocock and Israel Folau will both miss the sudden-death match after failing to overcome injuries sustained in the Wallabies nine-point win over Wales last week.
Pocock will be replaced by Ben McCalman, who will make his second start of the tournament at number eight, partnering Scott Fardy and returning vice-captain Michael Hooper in the Wallabies back row.
Kurtley Beale, who has produced several impressive performances from the bench this season, will take Folau’s place at full-back.
Moore will captain the side in his milestone game, while Giteau has shaken off an injury concern to line up at inside centre.
Moore and Giteau will become just the second pairing in history to earn their 100th Test cap for their country in the same match after Italy's Sergio Parisse and Martin Castrogiovanni shared the same honour in a Test match against Fiji in 2013.
In another historic occasion for Australian Rugby, Adam Ashley-Cooper will become the third-most capped Wallaby of all time in his 112th Test, overtaking flanker George Smith.
After an industrious cameo against Wales, lock Rob Simmons returns to the starting side with Dean Mumm moving to the reserves bench.
Wallabies head coach Michael Cheika said the 100 caps for Giteau and Moore were significant milestones but the best thing the side could do to honour the veterans would be to qualify for a World Cup Semi-Final.
“Stephen and Matt are very highly respected members of our team before they ever reached 100 Tests mark but this landmark makes all of us in the team very proud," he said.
“Every opportunity in the Gold Jersey is cherished and the 100th for these lads is a great opportunity for everyone to see how much they love playing for Australia.
“It is also a great chance for the lads playing against Scotland to improve their performance from our last game.
"As the tournament moves on we must continue to get better. That’s something we really want to do and believe we have in us.”
Australia: 15 Kurtley Beale, 14 Adam Ashley-Cooper, 13 Tevita Kuridrani, 12 Matt Giteau, 11 Drew Mitchell, 10 Bernard Foley, 9 Will Genia, 8 Ben McCalman, 7 Michael Hooper, 6 Scott Fardy, 5 Rob Simmons, 4 Kane Douglas, 3 Sekope Kepu, 2 Stephen Moore (c) 1 Scott Sio
Replacements: 16 Tatafu Polota-Nau, 17 James Slipper, 18 Greg Holmes, 19 Dean Mumm, 20 Sean McMahon, 21 Nick Phipps, 22 Matt Toomua, 23 Quade Cooper
Date: Sunday, October 18
Kick-off: 16:00 local (15:00 GMT)
Referee: Craig Joubert (South Africa)
Assistant Referees: Glen Jackson (New Zealand), Pascal Gauzere (France)
TMO: Ben Skeen (New Zealand)