Evergreen Adam Ashley-Cooper and fledgling Jordan Petaia have bolted into the most experienced Australian squad ever named to contest a Rugby World Cup.
Two midfield backs at polar ends of their careers have been included in Michael Cheika's 31-man squad unveiled in Sydney on Friday.
Boasting 45 caps per player, Cheika's Test-hardened group features a record three centurions in Ashley-Cooper, halfback Will Genia and prop Sekope Kepu along with two others poised to raise three figures in Japan - captain Michael Hooper and lock Rob Simmons.
Ashley-Cooper, 35, becomes the oldest Wallaby selected for a World Cup and Petaia, at 19, the youngest.
Ashley-Cooper has played the third-most Wallabies Tests (118) and scored the third-most tries (37). He joins Will Genia as the only Australians to attend four editions of the global tournament.
It rewards the Waratahs veteran for his bold call to spurn the riches of Japanese club rugby this year to pursue another crack at the Webb Ellis Cup.
At the other end of the spectrum is uncapped Queensland Reds back Petaia, a selection based on raw attacking potential.
Petaia suffered a serious foot injury in early March and has won selection on the back of recent club action on return to fitness.
Twelve of the squad were involved in the 2015 campaign, when Cheika defied the odds by overseeing a trip to the Twickenham final, won by the All Blacks. Seven of those players were also at the 2011 tournament.
A born-again James O'Connor attended 2011 but missed 2015.
O'Connor is among a raft of midfield backs named by Cheika. Nine of his squad have started a Test at inside or outside centre, and Petaia is poised to become the 10th.
It has left him thin on numbers in other positions.
Cheika has gambled on just two specialist halfbacks, while only five loose forwards have been named, including veteran David Pocock who hasn't played since March because of injury.
Cheika said his balance was carefully planned.
"It's also important that we select a squad that will handle the tournament play and our draw in particular at the Rugby World Cup, as well as maintain a strong competition for places in the team," he said.
Among the unluckiest omissions are fullback Tom Banks, halfback Joe Powell, hooker Tatafu Polota-Nau and flankers Liam Wright and Luke Jones, who will join the World Cup squad as train-on players at a 10-day preparation camp in New Caledonia.
They return to play Samoa in Sydney on September 7, two weeks out from an opening group game against Fiji in Sapporo. The other pool opponents are Wales, Uruguay and Georgia.
"These next few weeks are about building and adding that little extra edge as a squad and we'll be working hard to make sure we deliver on the qualities we want people to see when we run out on the field in Japan," Cheika said.
Wallabies World Cup Squad
Forwards: Allan Alaalatoa, Rory Arnold, Adam Coleman, Jack Dempsey, Folau Fainga'a, Michael Hooper, Sekope Kepu, Tolu Latu, Isi Naisarani, David Pocock, Izack Rodda, Lukhan Salakaia-Loto, Rob Simmons, Scott Sio, James Slipper, Taniela Tupou, Jordan Uelese.
Backs: Adam Ashley-Cooper, Kurtley Beale, Bernard Foley, Will Genia, Dane Haylett-Petty, Reece Hodge, Samu Kerevi, Marika Koroibete, Tevita Kuridrani, Christian Lealiifano, James O'Connor, Jordan Petaia, Matt Toomua, Nic White.