Fijian international Isa Nacewa is to return to play for Leinster in the 2015-16 season.
Nacewa, 32, made a try scoring debut for the Irish province in 2008 and made 126 appearances in five seasons.
He scored a total of 24 tries on his way to winning three Heineken Cup crowns and a Pro12 title with Leinster.
The fans' favourite left at the end of the 2012-13 season and has been working with Auckland Blues as a mental skills coach.
"We mentioned a few weeks back how our resources will be tested during the World Cup window and to be able to bring in a top quality player who we know will contribute massively to the environment when the more experienced lads are away, is huge for us," said Leinster coach Matt O'Connor.
"Isa hasn't played in a bit but he hasn't been alien to a rugby environment either working with the Auckland Blues as a mental skills coach and he has really enjoyed his time there.
"He has kept himself in good shape and was always in regular contact with some of the lads here like Leo (Cullen). But there is obviously still a feeling that he has unfinished business on the pitch and we are just delighted that he feels that it is with us."
Nacewa admitted he was "very excited" at the prospect of going back to Leinster.
"I spent five brilliant seasons there both on and off the pitch and while the decision to leave was right at the time, I also feel now that at 32 years I've still got something to give. If I didn't grab this opportunity, there will always be a sense of 'what if'."