Altior is one of only four five-day acceptors for the Matchbook Clarence House Chase at Ascot on Saturday.
Nicky Henderson's brilliant chaser stretched his unbeaten run over fences to 16 with victory in the Unibet Desert Orchid Chase at Kempton over Christmas and will be a long odds-on favourite at the weekend.
He faces a rematch with Un De Sceaux who chased him home in the Betfair Tingle Creek Chase at Sandown last month, four lengths adrift of his rival at the line.
Fox Norton, a dual Grade One winner for Colin Tizzard in the spring of 2017, stands his ground and could make his first start since pulling up in last season's 32Red King George VI Chase at Kempton.
The quartet is completed by Diego Du Charmil who was second in the Desert Orchid, 19 lengths behind Altior.