The 29 year old starts on the right wing in what will be his 5th test match for the Lions.
Welsh lock, Alun Wyn Jones, will lead the tourists at ANZ Stadium in Sydney on Saturday.
Ospreys second-row Jones replaces the injured Sam Warburton in a team showing six changes to the one that started last Saturday’s 2nd Test in Melbourne.
Sean O’Brien takes over from Warburton, and scrum-half Mike Philips has recovered from a knee injury to start instead of Ben Youngs.
Alex Corbisiero returns from injury to replace Mako Vunipola, who moves to the bench, Richard Hibbard makes his first starting appearance at hooker, while Toby Faletau makes his Test debut at No.8.
However, in what is the biggest shock of the team announcement, Irish centre and four-time Lions tourist, Brian O’Driscoll has been dropped from the squad completely and is replaced at 13 by Welsh centre Jamie Roberts.
British & Irish Lions Tour Manager Andy Irvine said: "It has been a great tour on and off the field. The hospitality we have received from the Australian people has been outstanding. The banter between the fans has been in great spirit and to date we have had two incredibly exciting Tests.
“It is amazing that the last three series between the Lions and the Wallabies have gone down to the last Test. In 1989 the Lions triumphed, in 2001 it was the Wallabies who won the series and now in 2013 we go to ANZ Stadium in Sydney with the series and the Tom Richards Trophy up for grabs.
“There is nothing between these two teams, with the last two Tests being decided in the dying moments. The Test is a sell out and the whole rugby world is looking forward to the match with great anticipation.”
Head Coach Warren Gatland said: “It all comes down to Saturday. Winner takes all. We know we can leave nothing in the tank and that only a complete performance will get us across the line. Picking this team was not easy and ultimately with several players available after recovering from injury the head overruled the heart in many selection decisions.
“It has been a challenging tour and we have had our fair share of injuries but we always knew that would be the case. Brian O’Driscoll is a great player and has had a wonderful career but for the final Test in Sydney we just felt Jamie Roberts' presence offered us something more. Mike Phillips and Alex Corbisiero were 1st Test selections and would probably have played in the 2nd Test if not for injury. Richard Hibbard, Toby Faletau and Sean O’Brien have also earned their starting places.”
British & Irish Lions versus Qantas Wallabies, July 6, Sydney
15. Leigh Halfpenny (Cardiff Blues/Wales)
14. Tommy Bowe (Ulster/Ireland)
13. Jonathan Davies (Scarlets/Wales)
12. Jamie Roberts (Cardiff Blues/Wales)
11. George North (Scarlets/Wales)
10. Jonathan Sexton (Leinster/Ireland)
9. Mike Phillips (Bayonne/Wales)
1. Alex Corbisiero (London Irish/England)
2. Richard Hibbard (Ospreys/Wales)
3. Adam Jones (Ospreys/Wales)
4. Alun Wyn Jones (Ospreys/Wales, capt)
5. Geoff Parling (Leicester Tigers/England)
6. Dan Lydiate (Dragons/Wales)
7. Sean O’Brien (Leinster/Ireland)
8. Tangaki Taulupe Faletau (Dragons/Wales)
Replacements
16. Tom Youngs (Leicester Tigers/England)
17. Makovina Vunipola (Saracens/England)
18. Dan Cole (Leicester Tigers/England)
19. Richie Gray (Scotland)
20. Justin Tipuric (Ospreys/Wales)
21. Conor Murray (Munster/Ireland)
22. Owen Farrell (Saracens/England)
23. Manusamoa Tuilagi (Leicester Tigers/England)