Where Or When, winner of last year’s Queen Elizabeth II Stakes, has been retired to stud.
The four-year-old, who was trained by Terry Mills, will stand at Cheveley Park Stud in Newmarket.
Where Or When won the Group One race at Ascot last year but was disappointing when finishing sixth behind Falbrav in the race last Saturday.
The Danehill Dancer colt ran his best race this season on his reappearance when he finished runner-up to Hawk Wing in the Juddmonte Lockinge Stakes at Newbury in May.
Where Or When recorded five wins from 18 starts in his racing career.
Robert Mills, assistant to his father, told the Racing Post: “Where Or When is the best horse we’ve ever trained and has run some fantastic races.
“His form figures don’t really do him justice, as he has been very unlucky in some of his races and came from a long way back when finishing fifth to Rock Of Gibraltar in the St James’s Palace at Royal Ascot, and you can’t give head starts to horses like him.
“He’s certainly been no mug and has been the highlight of my father’s 35 years in racing.”
Mills has kept an undisclosed portion of the colt and no stud fee has been decided yet.
“He has great confirmation and good size and he’s in the right place to stand at stud as they receive some fantastic mares,” Mills jnr added.