Paul Hanagan will replace retiring Richard Hills as retained rider for Sheikh Hamdan Al Maktoum.
Two-times champion jockey Hanagan will take up his new role when Hills retires on Dubai World Cup night on 31 March.
Hills saddled five British Classic winners for Sheikh Hamdan.
Angus Gold, racing manager to Sheikh Hamdan, said: "Having been such an integral part of the very successful Richard Fahey team for so long, I know that Paul will be a tremendous asset."
Gold said that Hanagan will still be given the opportunity to ride Fahey's horses when possible.
He added: "I would like to express our thanks to Richard Fahey, and feel sure that both he and Paul will be keen to maintain their relationship when Paul's commitments to Sheikh Hamdan allow, and we very much look forward to working with Paul in the coming years.
"At the same time, I would like to pay tribute to Richard Hills and thank him for the enormous contribution he has made to the success of the Shadwell horses over the last 20 years or so, and hope we can continue to count on his experience in the future."