Harry Herbert will leave his role as Sheikh Joaan Al Thani's racing adviser to concentrate on his Highclere Thoroughbred Racing operation.
Herbert has held the position since December 2013 and has overseen a fruitful spell for the Qatar-based team, including a Royal Ascot treble in 2014 and the 2000 Guineas success of the Hugo Palmer-trained Galileo Gold in 2016.
With the Al Shaqab squad having become increasingly concentrated in France, Herbert feels the time is right to leave his position and put all his efforts into the successful Highclere syndicate he started in 1992.
"Highclere is growing, particularly in Australia, and we are growing the National Hunt side of things, too. We have some great ideas and it's exciting times," Herbert told Press Association Sport.
"Al Shaqab have less horses in Britain than they do in France at the moment and the office has moved over there as well.
"I discussed it with the Al Shaqab team and they were very understanding. Highclere needs my attention and it was very much a mutual decision.
"It seems like the right time to do it, before the season really gets going."
Herbert will leave at the end of April.