Cuthbert, who has scored nine tries in his 18 appearances for Wales, will line-up in an experienced back-three with George North and Leigh Halfpenny - who was yesterday named on the BBC Sports Personality of the Year Award shortlist.
In total, Gatland's starting XV includes 11 of this summer's Lions squad - seven of which started the decider in Sydney.
"It's great to have Alex and Scott [Williams] available and they bring a lot of experience into the backline," said Gatland.
"Alex and the medical teams have worked really hard to ensure he is ready for this weekend and it's great to be able to bring him back into the side.
"There is a lot of experience in the pack for what is going to be a very physical game.
"We are looking to finish the series off well, the last three games against Australia have gone right down to the wire and I don't expect anything different this weekend."