D'Arcy went on the 2005 Lions tour of New Zealand
Ireland centre Gordon D'Arcy has been called up by the Lions because of injury concerns in their back division.
Riki Flutey has a knee ligament strain, Keith Earls sustained a minor shoulder injury against the Royal XV while Luke Fitzgerald has a chest infection.
Head coach Ian McGeechan said: "While the injuries are being treated by the medical team we felt it prudent to provide extra cover in midfield."
Leinster's D'Arcy is a team-mate of Brian O'Driscoll for club and country.
McGeechan added: "Gordon's partnership with Brian O'Driscoll is a proven one and can only benefit the Lions' squad here in South Africa.
"Gordon showed in the European Cup final (when Leinster beat Leicester 19-16) and the recent Barbarians match against England (when they won 33-26) that he is back to his best.
"He was on our reserve list and we had no hesitation in calling him up to the squad as he is an extremely experienced player who has played 41 times for his country."
D'Arcy, who featured in six provincial matches on the last Lions tour of New Zealand in 2005, as well as the pre-tour match against Argentina, will arrive in South Africa on Thursday, 4 June.
He could be summoned straight into action on Saturday for the third tour match against the Cheetahs, depending on the speed of recovery of Flutey and Earls.
Brian O'Driscoll and Jamie Roberts - who play against the Golden Lions on Wednesday - are currently the only fit specialist centres.
Wales stand-off James Hook also provides cover at inside centre, but having opted not to replace the injured Tom Shanklin from the original party, the Lions' resources are rather thinner at outside centre.
D'Arcy, 29, was sidelined with a broken arm in 2008 but has returned to form to help Ireland capture the Six Nations Grand Slam and Leinster win the Heineken Cup.