The Willie Mullins-trained 10-year-old claimed his second Festival success in the two-mile-five-furlong Grade One last March, following on from his victory in the 2015 Arkle Trophy.
He is a hot favourite to successfully defend his crown at Prestbury Park after becoming the first horse in history to win Ascot's Clarence House Chase three times on his latest appearance in January.
Whether Un De Sceaux is Mullins' only runner remains to be seen. The Closutton handler has also left in Bachasson, Djakadam, Douvan, Min, Yorkhill and Benie Des Dieux, but all have alternative targets.
The potential Irish challenge is completed by Henry de Bromhead's pair of Sub Lieutenant and Balko Des Flos, with both carrying the colours of Ryanair supremo Michael O'Leary's Gigginstown House Stud.
O'Leary is still trying to win the race he sponsors for the first time.
Ruth Jefferson has decided against running her stable star Waiting Patiently, but is still set to be represented by the ultra-consistent Cloudy Dream.
The eight-year-old was runner-up to Altior in last year's Arkle and has finished second on each of his four starts this season.
Jefferson said: "He's absolutely bouncing at the moment.
"He'd probably prefer better ground, but he does have form with cut in the ground.
"None of us know what the ground is going to be like at this stage. There's some rain forecast over the weekend and then a few showers at the start of the next week, so we'll just have to wait and see which way it goes.
"It could be good ground or it could be heavy. It is what it is. I'm not too worried about it, to be honest."
Colin Tizzard's popular veteran Cue Card will bring the house down if he can win this race for a second time having claimed victory in 2013.
The Paul Nicholls-trained pair of Frodon and Le Prezien, and L'Ami Serge from Nicky Henderson's yard are the other possibles.
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