Murtagh has enjoyed much success over his career
Top Flat jockey Johnny Murtagh is to become the number one rider for racehorse owner the Aga Khan's Irish-trained runners in 2011.
Murtagh left his job at Aidan O'Brien's Ballydoyle stable last week.
The Aga Khan has 120 horses in training in Ireland - 90 with John Oxx, to whom Murtagh was stable jockey between 1992 and 2003, and 30 with Mick Halford.
"I am thrilled to be renewing my association with His Highness's horses in Ireland," 40-year-old Murtagh said.
"We have shared some fantastic moments over the years and I have always enjoyed riding in the green and red colours.
"This will also give me an opportunity to ride for John Oxx again.
"I started off riding for Mr Oxx and it has always been a pleasure to be part of his team."
Murtagh rode 18 Group One winners for the Aga Khan during his previous spell with Oxx, including winning the 2000 Epsom Derby, the Irish Derby and the Prix de l'Arc de Triomphe on Sinndar.
He also partnered the likes of Alamshar, Kalanisi and Daliapour to big-race successes.
"I am delighted to have secured a world-class jockey like Johnny Murtagh as my retained rider in Ireland," the Aga Khan added.
"We have had some wonderful days in the past and we look forward to renewing our successful association.
"I believe it is vital to the continued success of my bloodstock operation to have a retained jockey in the countries where my horses are trained.
"This has been the situation in France for many years and I am most pleased now to have a similar arrangement in Ireland."
Christophe Lemaire is the retained rider for the French-trained horses and recently signed a two-year contract until 2012.
Murtagh's appointment would appear to be a big blow to his compatriot Fran Berry, who was appointed as Oxx's stable jockey earlier this year.