Sportal.co.nz 05.Jul.2013Getty Images
Smith has been rushed into Australia's starting line-up for the winner-takes-all clash after overcoming a knee injury suffered six weeks ago.
The 32-year-old says he is grateful for the chance to play in Saturday's sold-out blockbuster in Sydney, declaring the match a fitting end to his career in front of his friends and family.
"In terms of rugby it's the ultimate for me, to be selected within the starting XV for this decider, there's nothing higher for me at the moment," Smith enthused on Thursday.
"I'm very pleased that Robbie has gone my way in terms of selections, obviously Michael Hooper and Liam Gill played extremely well in the past two games but to get this opportunity is huge for me."
"I'm pretty sure it will be - no, it will be," Smith said when asked if Saturday's blockbuster will be his last Test.
"I've had a fantastic international career and knowing when to bow out and the legacy that I've left behind on the international stage I'm very proud of."
The legendary openside flanker played the last of his 110-Test matches against Wales at the end of 2009.
He joined the Brumbies on a short-term loan contract from Japanese club Suntory Sungoliath in March and was expected to start for the Wallabies in the opening Test after David Pocock suffered a season-ending knee injury.
A knee injury of his own threatened to derail his dream of a second series against the Lions but he will get his final farewell on Saturday night.
"This just caps it off. I retired in 2009 in Wales away from home with not too many friends and family there watching, this gives me the opportunity to play in front of them and also play in front of the Australian crowd and on home soil," he said.
"That will be fitting for my career to look back on and say I've finished on a great occasion, a big moment. I'm looking forward to that."
Coach Robbie Deans, who declared Smith is a better player now than when he played his last Test, said of Smith's selection ahead of Michael Hooper: "It was pretty straightforward really. It's not a big decision to select George. He's a bloke who's served Australian rugby enormously in the past.
"It's pretty evident he would have been part of this campaign if he hadn't had the misfortune of his injury.
"His recovery was remarkable and he's a great bloke to have around. He's very experienced, he will bring a lot of composure to the group.
"It's good to have someone like George alongside you in the game. There's not too many moments he hasn't experienced."
Smith, who revealed he was close to returning to the Wallabies fold for the 2011 Rugby World Cup after Deans approached him to play, is expecting a brutal breakdown battle against the Lions this weekend.
"I think they've played some really good rugby," Smith said.
"They've got some big running centres that we're going to play this weekend, they're very good at the breakdown as we saw last week, obviously (Sam) Warburton's not there this weekend but Sean O'Brien's a very good player.
"So I'm looking forward to a really good contest, a real robust game, hopefully not too many penalties and a lot of running rugby."