Ireland and Wales have named a combined total of 25 Lions in their respective squads for the autumn internationals.
Ireland head coach Declan Kidney has selected 12 players who toured with the Lions in 2005 or 2009, while his Wales counterpart Warren Gatland has named 13 in his 33-man party.
Triple Lions tourist Brian O’Driscoll leads the way for the Irish, captaining a squad that also includes Stephen Ferris, John Hayes, Jamie Heaslip, Donncha O' Callaghan, David Wallace, Tommy Bowe, Gordon D'Arcy, Keith Earls, Shane Horgan, Rob Kearney and Ronan O'Gara.
For Wales, Gethin Jenkins, Adam Jones, Matthew Rees, Alun Wyn Jones, Ryan Jones, Martyn Williams, Mike Phillips, Stephen Jones, James Hook, Tom Shanklin, Shane Williams, Leigh Halfpenny and Lee Byrne provide a heavy Lions contingent.
Wales also include uncapped duo Scott Andrews and George North, while Ireland could hand senior debuts to Leinster lock Devin Toner and Munster utility back Johne Muprhy.
Wales face all three of the world’s leading sides, kicking off with Australia on November 6, followed by South Africa on November 13, with a clash with Fiji coming a week before a mouth-watering encounter with the All Blacks.
Ireland also face the All Blacks and the Springboks, as well as Samoa and Argentina, on successive weekends at their new Aviva Stadium home in Dublin.
For Ireland, 2009 Lions skipper Paul O’Connell and Test wing Luke Fitzgerald are notable absentees due to injury, while HSBC Player of the Tour Jamie Roberts is missing from the Welsh squad for the same reason.
"It is going to be a demanding month for the squad and the first time we have played four games in the Guinness series,” said Ireland head coach Kidney.
"We felt it was important to have 30 fit players to choose from in terms of setting the foundations for November and it was better for those who picked up knocks to be assessed back in the provinces and when they have the all clear, to come back into the squad.
"Jerry (Flannery) and Luke (Fitzgerald) are in that position, as are fellas like Tomas (O'Leary) and Leo (Cullen) who may well come back into the mix depending on their recoveries and game time that they may need to build up over the next couple of weeks."
"We need everybody in a position to be able to contribute in training and while we may well leave a window for those coming back, all the players in the squad are deserving of their chance. There are a lot of players who are unlucky not to make this squad, but the door will remain open to them also during November to join up with the panel."
Fresh from signing a new four-year contract, Wales boss Gatland is fully focused on the challenge posed by an Australian side who will provide the Lions’ next opposition in 2013.
The Wallabies may have lost out to New Zealand in this year’s Tri Nations but two victories over the Boks and a series of outstanding attacking performances suggest they are a side very much on the up.
"Australia have been devastating at times so far this season. In 2011 (at the Rugby World Cup) I think they are going to be firing," said Gatland.
"This is a really big game for us. We were disappointed last year that we didn't do as well as we can against them but we have a few big players back this year.
"From our squad the only really absentee is Jamie Roberts but, apart from him, we have been able to select from a position of strength.
"So we are really looking forward to and are excited about Australia. They will be well prepared after a good Tri Nations and facing the All Blacks in Hong Kong before they arrive, but we have a good couple of weeks to work hard and get up and ready.”
Forwards: Rory Best (Banbridge/Ulster), Tony Buckley (Shannon/Munster), Tom Court (Malone/Ulster), Sean Cronin (Buccaneers/Connacht), Stephen Ferris (Dungannon/Ulster), John Hayes (Bruff/Munster), Cian Healy (Clontarf/Leinster), Jamie Heaslip (Naas/Leinster), Marcus Horan (Shannon/Munster), Denis Leamy (Cork Constitution/Munster), John Muldoon (Galwegians/Connacht), Donncha O' Callaghan (Cork Constitution/Munster), Sean O'Brien (Clontarf/Leinster), Mick O'Driscoll (Constitution/Munster), Mike Ross (Clontarf/Leinster), Donnacha Ryan (Shannon/Munster), Devin Toner (Lansdowne/Leinster)*, Damien Varley (Garryowen/Munster), David Wallace (Garryowen/Munster),
Backs: Isaac Boss (Terenure College/Leinster), Tommy Bowe (Ospreys), Gordon D'Arcy (Lansdowne/Leinster), Gavin Duffy (Galwegians/Connacht), Keith Earls (Thomond/Munster), Shane Horgan (Boyne/Leinster), Robert Kearney (UCD/Leinster), Johne Murphy (Young Munster/Munster)*, Ronan O' Gara (Cork Constitution/Munster), Brian O'Driscoll (UCD/Leinster), Eoin Reddan (Lansdowne/Leinster), Jonathan Sexton (St.Mary's College/Leinster), Peter Stringer (Shannon/Munster), Andrew Trimble (Ballymena/Ulster), Paddy Wallace (Ballymena/Ulster)
Forwards: Gethin Jenkins (Blues), Paul James (Ospreys), Adam Jones (Ospreys), John Yapp (Blues), Scott Andrews (Blues)*, Matthew Rees (Scarlets), Huw Bennett (Ospreys), Richard Hibbard (Ospreys), Alun Wyn Jones (Ospreys), Bradley Davies (Blues), Deiniol Jones (Blues), Ian Gough (Ospreys), Dan Lydiate (Dragons), Jonathan Thomas (Ospreys), Ryan Jones (Ospreys), Sam Warburton (Blues), Martyn Williams (Blues), Rob McCusker (Scarlets)
Backs: Michael Phillips (Ospreys), Richard Rees (Blues), Tavis Knoyle (Scarlets), Stephen Jones (Scarlets), Dan Biggar (Ospreys), James Hook (Ospreys), Andrew Bishop (Ospreys), Jonathan Davies (Scarlets), Tom Shanklin (Blues), Shane Williams (Ospreys), Leigh Halfpenny (Blues), Will Harries (Dragons), George North (Scarlets)*, Lee Byrne (Ospreys), Tom Prydie (Ospreys)
* denotes uncapped player