Night Of Thunder and Charm Spirit are among 11 horses declared for the Queen Elizabeth II Stakes at Ascot on Saturday.
Richard Hannon's Night Of Thunder has failed to get his head in front since his memorable 2000 Guineas triumph in the spring, but is closely matched with Freddy Head's French raider Charm Spirit on their recent meeting at Longchamp.
Charm Spirit clinched the Prix du Moulin in Paris last month, with Night Of Thunder just half a length away in third.
Hannon is also represented by Toormore but has, as expected, taken out the Breeders' Cup-bound Toronado on account of the likely testing conditions on Champions Day.
Kieren Fallon has been booked to ride Toormore and connections are cautiously optimistic about his chances.
Tim Palin, racing manager for owners Middleham Park Racing, said: "We're delighted to have Kieren riding the horse.
"When you're going into these races you are looking for big-time jockeys as for them, it's just another race.
"Kieren has probably ridden more Group One winners than I've had hot dinners, so it's great to have him on side and we'll talk tactics nearer the time.
"Richard Hannon tells me the horse is in really good form, so fingers crossed."
The Michael Stoute-trained filly Integral has already struck twice at Group One level this year, landing the Falmouth Stakes and the Sun Chariot, and is pitched in against the boys.
Brian Ellison's stable star Top Notch Tonto was runner-up was a year ago and is again expected to put up a bold show with the ground set to be in his favour.
Custom Cut has enjoyed a fantastic season for David O'Meara, winning five races on the bounce, and steps up to the highest level after having been supplemented on Monday.
Aidan O'Brien relies upon Kingsbarns, with Ger Lyons' Brendan Brackan joining him on the trip from Ireland.
Andrew Balding's Tullius, the Roger Charlton-trained Captain Cat and Graphic from William Haggas' yard complete the field.
Along with Toronado, Dermot Weld's Mustajeeb was the only other horse not declared.
