Mortlock's return is crucial with Mark Gerrard and David Lyons out
England v Australia
Stade Velodrome, Marseille
Saturday, 6 October
Kick-off: 1400 BST
Live on BBC Radio 5live and the BBC Sport website
Stirling Mortlock has been passed fit to lead Australia in their World Cup quarter-final against England.
The centre missed Australia's last two games with a dislocated shoulder but is back for the crunch clash in Marseille.
Australia have left the tournament's leading try scorer, wing Drew Mitchell, on the bench and replaced him with the more powerful Adam Ashley-Cooper.
Otherwise, it is the same side that beat Wales 32-20 at the Millennium Stadium in the group stages.
Mortlock's return was expected, but is still a welcome relief for coach John Connolly with wing Mark Gerrard and back-rower David Lyons already ruled out of the tournament.
Fly-half Stephen Larkham, who has a knee injury, and utility back Scott Staniforth (shoulder) are also unavailable for Saturday's match.
It means, alongside Mitchell, Julian Huxley is the only other back on a replacements bench stacked with forwards - highlighting Australia's intentions to try to match England's massive pack.
"England are a very dangerous team," said Connolly.
"Their set-piece has been the cornerstone for years, they have incredible speed out wide and Jonny Wilkinson steers them around exceptionally well.
"When you look at our results through the pool games, you'd have to say we're pretty happy with where we're at.
"But we're very conscious that we have to improve considerably on that to go any further in the tournament."
And Connolly also dismissed suggestions young fly-half Berrick Barnes, who is just 21, would be out-classed by Wilkinson in Marseille.
"He has the skills set and the mentality to be able to handle the pressure of the World Cup. We're quite confident with him," said Connolly.
Australia lost to England in the 2003 World Cup final in Sydney with Wilkinson slotting an extra-time drop-goal.
Since then, Australia have beaten England four times in five matches. Australia's last defeat to England was a 26-16 loss at Twickenham in 2005.
Australia: Chris Latham; Adam Ashley-Cooper, Stirling Mortlock, Matt Giteau, Lote Tuqiri; Berrick Barnes, George Gregan; Wycliff Palu, George Smith, Rocky Elsom, Dan Vickerman, Nathan Sharpe, Guy Shepherdson, Stephen Moore, Matt Dunning.
Replacements: Adam Freier, Al Baxter, Hugh McMeniman, Stphen Hoiles, Phil Waugh, Julian Huxley, Drew Mitchell.