Nineteen in line for Gold Cup
The Queen's Estimate could face a maximum of 18 rivals in defence of her Gold Cup crown at Royal Ascot on Thursday.
The Sir Michael Stoute-trained five-year-old became the first horse in the 207-year history of the stayers' championship to carry the colours of a reigning monarch to victory, adding to her Queen's Vase success in 2012.
However, the mare has an even taller order this time as she has not run yet this season.
Leading Light, winner of the Queen's Vase 12 months ago, heads the ante-post market.
Victorious in the Ladbrokes St Leger in September, Aidan O'Brien's charge has already demonstrated his well-being this term when taking the Vintage Crop Stakes at Navan with some authority.
The Ballydoyle handler also has El Salvador, Ernest Hemingway and Eye Of The Storm, while other Irish-trained possibles are Simenon, last year's runner-up for Willie Mullins, Royal Diamond, Saddler's Rock, Ralston Road, Missunited and Pale Mimosa.
A horse who will carry strong support on the home front is Brown Panther, bred and co-owned by former England striker Michael Owen. The Tom Dascombe-trained six-year-old has been in the form of his life this season, chalking up convincing victories in Chester's Ormonde Stakes and the Henry II Stakes at Sandown.
Marco Botti has left in Tac De Boistron, winner of the Prix Royal-Oak and Sagaro Stakes, while Godolphin rely on Ahzeemah, trained by Saeed bin Suroor.
German raider Altano could try to improve on his fifth place in the race last year for trainer Andreas Wohler.
Completing the list of 19 six-day confirmations are Oriental Fox, Whiplash Willie, Havana Beat and Shwaiman.