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."
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