Pyledriver is among a field of 12 for the Pertemps St Leger at Doncaster.
William Muir’s stable star will try to complete his fairytale rise on Saturday, after victories in the King Edward VII Stakes at Royal Ascot and the Great Voltigeur at York.
The Lambourn trainer’s ace will face the might of Ballydoyle, with Aidan O’Brien three-handed as he aims to win the Leger for a seventh time. Irish Derby hero Santiago heads his team, completed by Dawn Patrol and Mythical.
Joseph O’Brien’s Galileo Chrome and Sunchart, trained by Andy Slattery, are the other Irish-based runners.
Ed Walker has declared English King, but the Lingfield Derby Trial victor is more likely to go to France for Sunday’s Juddmonte Grand Prix de Paris at ParisLongchamp.
Walker told Sky Sports Racing: “We’ve declared for the St Leger – but the plan for a long time has been to head to France, and we’re still very much leaning that way.
“We’re just very concerned about travel arrangements and the changing world of Covid. With numbers increasing here, the last thing in the world we want is for France to slap a two-week quarantine on people coming from England to France and then we can’t go – so we’re just covering all angles.
“We have to decide finally by 8.30am tomorrow, so it basically gives us an extra day to see how the water lies. If everything is equal we’ll be going to Paris on Sunday.
“Tom (Marquand) is booked to ride in the Leger, because I told Frankie (Dettori) a few weeks ago we were very unlikely to run in the Leger – and as far as I understand, Frankie is riding Santiago.
“Frankie is already (set to be) in France to ride Stradivarius, so I think we’ve got everything covered. It’s a huge day for Bjorn (Nielsen, owner) with Stradivarius back over a mile and a half in the Prix Foy on his way to the Arc.
“I think English King is as good as I’ve had him all year, to be honest. I know he’s got doubters now but I’m not one and I’m hoping this weekend he’ll prove them all wrong.”
Hukum, winner of the Geoffrey Freer Stakes at Newbury, will bid to give his trainer Owen Burrows a first Classic triumph at Doncaster.
Berkshire Rocco, Mohican Heights, Subjectivist and Tyson Fury complete the dozen hopefuls.
The three withdrawals at the 48-hour final declaration stage were Max Vega, Tiger Moth and Believe In Love – due to run in the Park Hill Stakes at Doncaster on Thursday afternoon.
Richard Hannon’s unbeaten colt Chindit faces six opponents in the Group Two bet365 Champagne Stakes.
Among the Ascot Listed race winner’s rivals are the experienced pair of Broxi and Devious Company, as well as Owen Burrows’ Albasheer and Irish raider State Of Rest.
Two past winners of the Prix de la Foret – Limato and One Master – are among eight runners in the Group Two bet365 Park Stakes.
Wichita, runner-up in the 2000 Guineas, and Jersey Stakes scorer Molatham represent the Classic generation.