UPDATE: Wallabies coach Michael Cheika has named teenager Jordan Petaia in a World Cup squad that he wants to be "unpredictable".
Asked at Friday's squad announcement what he expected his team's style to be at the World Cup, Cheika said there was one characteristic he truly wanted from his side.
"I'd say we'll be a little bit unpredictable in Japan, that's a bit of our theme this year," he said.
"At the World Cup, every game is a grand final. And how you approach that-- you don't look any further down the road that what's in front of you,"
Queensland rookie Petaia is the only bolter in the squad and the only candidate to make his debut in a fairly experienced group.
Even he could be considered an expected addition, given his standing among many pundits and the form he showed even in limited Super Rugby showings this season.
Petaia missed most of the Super Rugby season with a Lisfranc injury and has played just 70 minutes in club rugby on his return but his potential is so high that he demanded to be included on the plane to Japan.
Cheika said Petaia had shown enough in his limited game time to demand a spot.
"He came on the (2018 Spring) tour as a development player and then was literally an inch away from making his Test debut against Italy until he got a slight hamstring strain in training on the Tuesday and we didn't want to risk that for him going forward and then he was close the week after in England, again the injury (kept) him out and then he was very close to getting selected here in the second New Zealand game," he said.
"We just thought, at that stage, we just thought we'd made the decision that we would be bringing him on the tour here.
"So, we made that choice and I think he's just impressed me with his durability and his ability to learn fast.
"He's just getting straight into the team's way of play and he's got a good connection with the lads. He's fitted in really nicely so I see so much potential there, it's about getting some of that over the next two months."
Petaia said he was confident in his fitness as he prepared for the biggest opportunity of his career.
"I am stoked. It’s amazing I get to share this journey with the boys and to represent my country and my family," he said.
"I am feeling really good. The next two weeks is going to be even better for all the boys, with lots of conditioning.
"I feel like my body is in a good place right now and it’s just a chance to now put those one percenters in for the World Cup."
Of the 31-man squad, 18 will be featuring in their first Rugby World Cup campaign while 13 have been there at least once before.
Cheika will take three specialist hookers in Folau Fainga’a, Tolu Latu and Jordan Uelese, opting to leave Tatafu Polota-Nau behind.
In the forwards, there is no Will Skelton despite speculation as late as Tuesday that the door was still open for the mammoth lock to return to the Wallabies fold.
Luke Jones has been squeezed out of the mix in the final World Cup cull, with Izack Rodda, Rory Arnold, Adam Coleman and Rob Simmons the second row contingent.
Jack Dempsey has been included in the squad despite suffering a shoulder injury in club rugby that had him under a cloud.
Cheika said he was confident Dempsey would be fit to play in the side's September 7 Test against Samoa and would bring a point of difference to the squad in Japan.
"I think he'll definitely be available in the game against Samoa and I wanted him to be 100 per cent right to jump in to training from day one now because he hasn't been with the squad for a bit," he said.
"Our medicos have confirmed that that'll be the case.
"He's got that little bit of X factor Jack, he can cover multiple of positions in a back row, even seven at a pinch if he had to, depending on the situation because he's done that before.
"He's a lineout player as well and he's a very good ball carrier and he's an aggressive style player and I think that that's going to be essential."
No. 7 David Pocock will also fly to Japan, despite missing more than six months of rugby with a niggling calf injury.
Cheika said this week he also expected Pocock to come back in their final pre-World Cup Test against Samoa next weekend but even if he doesn’t play in that Test, the superstar never looked like missing out on the final 31.
While Cheika has taken the cautious route with his hookers, he has opted to take the risk of picking just two halfbacks for the tournament for the second campaign in a row.
In 2015 Cheika had the option of Matt Giteau at a pinch, backing up Will Genia and Nick Phipps, but this year there are no clear no. 9s outside of the duo of Genia and White.
Should one be struck down with injury, the Wallabies would have to replace them permanently in the squad and would be unable to field that replacement for a full 48 hours after the change.
James O'Connor has continued a remarkable return to the Test fold with his selection in the group, eight years after his last World Cup appearance.
The back who might feel the unluckiest to miss out might be Brumbies fullback Tom Banks, who has been in and out of the Test 23 so far this winter.
Banks was the form fullback in Australia’s Super Rugby sides but with the ability to play just one position, he has been pipped by utilities Adam Ashley-Cooper, Reece Hodge and fullback-winger Dane Haylett-Petty.
Ashley-Cooper will become just the second Wallaby behind George Gregan to play in a fourth consecutive Rugby World Cup, despite having played limited minutes in the Rugby Championship.
Cheika said Ashley-Cooper's versatility as well as his invaluable experience ultimately got him the nod.
"If you look at the composition of the squad - 18 who have never been to a World Cup and 13 who have. So, we'll definitely be looking at those 13 to have an impact because that little bit of extra experience makes those younger players who haven't been there feel comfortable enough to express themselves and go for it," he said.
"We're going to get on that plane, whenever we're going on the 8th, just thinking about, 'Well, we can't wait for this tournament to start', and I think players with experience like Ashley-Cooper help that happen.
"On the field, i think the thing that probably got him into that space was his defensive knowledge, his communication in defence and making sure we've got the ability to have someone who can cover 13, wing spots in a possible finishers or if he's starting he can move around the team from 13 to wing, because that's quite important to have in the squad."
The flyhalf trio of Christian Lealiifano, Bernard Foley and Matt To’omua have all been named in the 31.
Australia will fly to Noumea on Friday night for a 10-day camp before returning to Sydney to face Samoa at Bankwest Stadium in Parramatta on Saturday September 7.
Jones, Banks, Polota-Nau, Liam Wright and Joe Powell will all be part of the extended squad until the group leaves for Japan on Sunday September 8.
The Wallabies open their Rugby World Cup campaign against Fiji on Saturday September 21 at the Sapporo Dome, kicking off at 2:45pm AEST
Wallabies squad for the 2019 Rugby World Cup
Allan Alaalatoa (34 Tests, Brumbies, 25)*
Rory Arnold (22 Tests , Brumbies, 29)*
Adam Coleman (33 Tests, Melbourne Rebels, 28)*
Jack Dempsey (11 Tests, NSW Waratahs, 25)*
Folau Fainga’a (11 Tests, Brumbies, 24)*
Michael Hooper (c) (95 Tests, NSW Waratahs, 27)
Sekope Kepu (105 Tests, NSW Waratahs, 33)
Tolu Latu (15 Tests, NSW Waratahs, 26)*
Isi Naisarani (4 Tests, Melbourne Rebels, 24)*
David Pocock (77 Tests, Brumbies, 31)
Izack Rodda (21 Tests, Queensland Reds, 22)*
Lukhan Salakaia-Loto (15 Tests, Queensland Reds, 23)*
Rob Simmons (97 Tests, NSW Waratahs, 30)
Scott Sio (58 Tests, Brumbies, 27)
James Slipper (90 Tests, Brumbies, 30)
Taniela Tupou (15 Tests, Queensland Reds, 23)*
Jordan Uelese (3 Tests, Melbourne Rebels, 22)*
Adam Ashley-Cooper (118 Tests, NSW Waratahs, 35)
Kurtley Beale (87 Tests, NSW Waratahs, 30)
Bernard Foley (69 Tests, NSW Waratahs, 29)
Will Genia (104 Tests, Melbourne Rebels, 31)
Dane Haylett-Petty (32 Tests, Melbourne Rebels, 30)*
Reece Hodge (37 Tests, Melbourne Rebels, 24)*
Samu Kerevi (29 Tests, Queensland Reds, 25)*
Marika Koroibete (23 Tests, Melbourne Rebels, 27)*
Tevita Kuridrani (60 Tests, Brumbies, 28)
Christian Lealiifano (22 Tests, Brumbies, 31)*
James O’Connor (47 Tests, Queensland Reds, 29)
Jordan Petaia (uncapped, Queensland Reds, 19)*
Matt To’omua (46 Tests, Melbourne Rebels, 29)
Nic White (26 Tests, Rugby Australia, 29)*
*Uncapped at a Rugby World Cup
Wallabies Rugby World Cup pool
All times AEST/AEDT
Australia vs Fiji, Sapporo Dome, Sapporo, Saturday September 21, 2.45pm
Australia vs Wales, Ajinomoto Stadium, Tokyo, Sunday September 29, 5.45pm
Australia vs Uruguay, Oita Bank Dome, Oita, Saturday October 5, 3.15pm
Australia vs Georgia, Shizuoka Stadium, Shizuoka, Friday October 11, 9.15pm