Pour Moi, the winner of this year's Derby at Epsom, has been retired after suffering a serious leg injury.
The colt was hurt while being prepared by trainer Andre Fabre for October's Prix de l'Arc de Triomphe at Longchamp.
Pour Moi has been retired to stud by owners, the Irish-based Coolmore Stud.
At June's Derby, winning jockey Mickael Barzalona famously celebrated before reaching the finishing line, as the French-trained horse beat Treasure Beach and Carlton House.
Fabre said: "He badly over-reached himself on his off-fore and I'm afraid he won't run again. It's difficult to mend.
"What he did at Epsom was amazing, to go from last to first. For a horse to get there so easily, the turn of foot he showed was a sign of great ability.
"I'm sure he will be a super sire. He's a beautiful, well-bred colt with a fantastic action and a change of pace."