Tidal Bay heads the weights after 22 horses were confirmed for the Hennessy Gold Cup at Newbury on Saturday.
The enigmatic 11-year-old ended last season with victory in the bet365 Gold Cup at Sandown and made a winning return back over smaller obstacles in the John Smith's Hurdle at Wetherby.
Champion trainer Paul Nicholls could also saddle Harry The Viking, who is at the other end of the weights on 10st 2lb, but stable companion Michel Le Bon is a notable defection.
The ante-post favourite for the race is Nicky Henderson's Bobs Worth (11st 6lb), last seen winning the RSA Chase at the Cheltenham Festival. Henderson may also saddle Roberto Goldback, who made a winning start for new connections at Ascot.
Other leading contenders include The Package, Hold On Julio, Frisco Depot and Saint Are. Last year's Hennessy hero Carruthers is also in contention - as is the 2010 winner Diamond Harry.
There is also a strong representation from Ireland, headed by the Mouse Morris-trained First Lieutenant.
Irish National winner Lion Na Bearnai and Magnanimity from Dessie Hughes' yard may also make the journey.
Frisco Depot's trainer Charlie Longsdon is hopeful of a bold run. The eight-year-old showed smart form for Hughes in Ireland and was in the process of running a big race at Ascot on his debut for Longsdon when falling three fences from home. Sam Waley-Cohen, son of part-owner Robert, will keep the ride this weekend.
Longsdon said: "It was the lightest Sam had ever ridden when he rode him last time. He will probably do 2lb over weight on the day and I think we will put a stronger bit in his mouth because he was a bit keen last time.
"I don't think the ground will be a problem as all his runs in Ireland were on heavy ground."
19 June 2013
Perfect Annecdote at AscotGodolphin swoop for Libertarian
Doyle hits treble top on Rizeena
Doyle fits the bill in Hunt Cup
Toronado pointed towards Goodwood
O'Brien keeps faith in Camelot
Kazeem crowned Prince of Ascot
Cambridge Dun and dusted
Perfect Ten in Jersey
Plenty of rain needed for Approval
Banoffee pencilled in for Haydock
Classic rematch in Coronation
Guest has excellent chance
Brittain sweet on Rizeena
Team O'Brien hope for perfect Ten
Chigun aiming for Cambridge glory
Camelot bids for redemption
O'Neill ace proves too sharp
Ballydoyle in command in Coventry
Dawn delivers in thriller
Sole powers to sprint glory
O'Brien sounds War cry
18 June 2013
Stevens is king of the CastleAl Thani snaps up Sandiva
Minute's silence remembers Cecil
Duntle on Cambridge duty
Alive and Just in Ribblesdale mix
Passage heads Gold field
Deegan considers Soprano options
Toro out for Palace glory
Cecil's words not lost on Ponsonby
Dawn out for Palace redemption
Hawkwood supplemented for Hardwicke
Flotilla To Drop Back In Trip
Cecil's Chigun in Cambridge action
Al Kazeem and Camelot clash again
De Kock hoping to make history
War ready for Royal Ascot battle
Kingdom set to reign over Ascot
17 June 2013
Magician set for Palace showdownCat clings on for Carroll
Three more winners for Lady Cecil
Monaghan delivers on Midnight
Treve in stunning Diane win
Sapphire target for Trees
Beckett mulls Secret options
Nicholls has broken wrist
16 June 2013
Songbird aiming to fly highMovie has Newmarket on radar
Fahey juveniles primed for action
Stubbs leads O'Brien Coventry team
Salsify on summer break
Kempton target for Benbulben
Top trio head Palace runners
Shea Shea shoots for Stand glory
Animal heads Queen Anne field
Saint-Cloud aim for Dunaden
Magician to be declared for Palace
Soul all heart in York sprint
Kingsgate rules Musselburgh
Sam too sharp for rivals
Hughes makes it pay with Knight
Balding on mark with double
Morawij in a hurry in Scurry
Bartley is queen for a day
Big guns to clash in Coronation