Shaun Edwards will return to club coaching from next season after London Irish confirmed their acquisition of the Wales defence coach on a part-time basis.
The 45-year-old has helped Wales to two Six Nations Grand Slams since being added to Warren Gatland's coaching staff in 2008, and he has a contract with the Welsh Rugby Union through to the 2015 World Cup.
Under the terms of that agreement Edwards is allowed a period of time to work with an Aviva Premiership club, and he will spend one day a week with the Exiles after returning from Wales' summer tour to Australia.
Edwards is one of the most-decorated coaches in the game after a glittering spell at Wasps that saw them win Premiership titles in 2003, 2004, 2005 and 2008, the Anglo Welsh Cup in 2006 and the Heineken Cup in 2004 and 2007.
The Wigan rugby league great left Wasps shortly after last year's World Cup and Irish confirmed his capture just a day after Toby Booth, Justin Bishop and Neal Hatley left the club, with Booth and Hatley heading to join Bath.
"I'm excited at the opportunity of being involved in a Premiership club set-up again," said Edwards.
"London Irish has some fantastic players who I am looking forward to working with. The squad has put in some great performances this season and have been unlucky not to come away with more wins.
"I want to work with the team to see how we can then turn those frustrating last-minute defeats into victories."
And Edwards has set his sights on at the very least getting Irish back into the Heineken Cup after their disappointing seventh-place finish this season.
He told Sky Sports News: "I've looked at the record of London Irish and they lost a lot of close games this year and if they can turn them into victories they will be challenging for a play-off spot, certainly we want to be in a Heineken Cup place.
"It was only a few years ago that London Irish narrowly lost in the Grand Final against Leicester, so it's an ambitious club.
"(Irish director of rugby) Brian Smith's got a great eye for players, particularly in the southern hemisphere. I'm pretty excited about the squad he's building for next season."
Former England attack coach Smith will also take on a more hands-on coaching role to run the team's offensive play.
Smith said: "Shaun is a world-class coach and he has been responsible for introducing a defensive system that has changed the shape of the modern game, consistently producing watertight defences in the Premiership, Six Nations, Lion's tours and Rugby World Cups.
"He is a tough, hard-nosed coach, who I am confident will, alongside me, help to bring out the very best in the London Irish squad.
"We will have a strategy in place for next season to slash the numbers of points we concede in the Aviva Premiership. If we can do that then, this time next year, we can be a top-four team and two games away from silverware."
Irish also confirmed they are looking to announce the appointment of a new forwards coach shortly.
The WRU, meanwhile, added their endorsement to the move.
"Shaun is always going to be a coach in demand and this new arrangement with London Irish will be of mutual benefit to all concerned," said a WRU spokesperson.
"It will keep Shaun at the very cutting edge of the game at a domestic level, as did his prior arrangement with London Wasps and that can only be of benefit to Wales.
"We have been more than pleased to be able to negotiate terms with all of our current coaching staff to keep them in place until at least the culmination of the 2015 World Cup and are just as pleased to wish Shaun well with his new role at London Irish."