Trained by David Marnane, Dandy Boy was last seen winning the Wokingham at Royal Ascot and has been added to the field at Headquarters to the tune of £30,000.
Marnane said: “He pleased us going into Ascot and has pleased us as much, if not more, since coming out of Ascot.
“He’s been a phenomenal horse for us and to win a third big handicap like that in the manner he did shows what a good horse he is on his day.
“He’s a fragile horse and when they are right and well you have to take your chance.
“The ground was just good at Ascot, it was touch and go whether he would run because of softer ground but he’s a little bit older now and he is fragile so maybe he enjoys a bit ease in the ground now.
“I think he moved better at Ascot on the slightly easier surface.”
Also supplemented was the Richard Hannon-trained Strong Suit, who will be having his first start at six furlongs since finishing second to Dream Ahead in the Middle Park Stakes as a two-year-old.
21 horses remain at the confirmation stage, but Aidan O’Brien has taken out crack miler Excelebration.
However, the Ballydoyle handler can still call on Irish 2,000 Guineas winner Power, as well as After and Reply.
Ante-post favourite Bated Breath, second in the King’s Stand behind Little Bridge, stands his ground for Roger Charlton, with James Fanshawe’s Society Rock being left in after his unlucky fifth to Black Caviar in the Diamond Jubilee Stakes at the Royal meeting.
Hoof It and the Paul Messara-trained Australian raider Ortensia are other notables.