Experienced fly-half Andy Goode will leave Wasps at the end of the season to join Premiership rivals London Irish.
The 34-year-old is the second-highest points scorer in Premiership history, with 2,147 for Leicester, Saracens, Worcester and Wasps.
Goode, who won 17 England caps, turned down the chance to stay at Wasps in a coaching capacity.
"He has a wealth of experience to offer and is also a leader," said Exiles director of operations Bob Casey.
|Premiership's all-time leading points scorers|
|1. Charlie Hodgson||(Sale and Saracens)||2,427|
|2. Andy Goode||(Leicester, Saracens, Worcester and Wasps)||2,147|
|3. Olly Barkley||(Bath, Gloucester and London Welsh)||1,605|
|4. Jonny Wilkinson||(Newcastle)||1,489|
|5. Nick Evans||(Harlequins)||1,295|
"Andy has proven himself as one of the best fly-halves in the Premiership and we are delighted he has signed for us."
Goode, who is out of contract at Wasps at the end of the season, said he wanted to extend his playing career before making the switch to coaching.
"I have huge respect for the coaches and the players at Wasps, and I am very grateful for them offering me the opportunity to start a coaching career here," he said.
"But I love playing the game and I'm excited to be joining London Irish, which is another club with fantastic opportunities ahead, following a similar re-building process to Wasps.
"The facilities are very impressive and having spoken to the management and coaching staff, it is a club I am really excited to be joining.
"I have had two brilliant years at Wasps and will leave with many fond memories."
The Coventry-born fly-half - and lifelong Sky Blues fan - set a Premiership record of 33 points against the Exiles earlier this season with a fairytale performance on Wasps' first appearance at the Ricoh Arena.
Goode won five Premiership titles and two Heineken Cups during nine seasons with Leicester, either side of a stint at Saracens, before moving to French side Brive, Worcester and then on to Wasps as well as a short spell in Super Rugby with the Sharks.
His England career came between 2005 and 2009, but Goode never truly established himself in the number 10 jersey for his country during a difficult time for the national side.
However, he proved himself a valuable asset at club level, with only Saracens fly-half Charlie Hodgson bettering his points tally in the top flight.
"We would have loved for Andy to stay at Wasps in a coaching capacity next season, but we fully understand his decision to play on at London Irish, during an exciting time for that club as well," said Wasps director of rugby Dai Young.
"Goodey has been a tremendous ambassador for Wasps since joining two seasons ago, both on and off the field. His performance against London Irish at our first game at the Ricoh Arena will live long in the memory."
Meanwhile, London Irish have also signed utility back Andy Short from Bristol on loan until the end of the season.
The 23-year-old former England Under-20 international is set to rejoin Worcester when his Bristol contract expires in the summer.
''The opportunity came up for us to bring Andy in for the rest of the season and it is a good fit for all involved," said Exiles head coach Glenn Delaney. "Andy will suit our style of play and be an asset to the group for the remainder of the season."