Muirhead is the sole Irish contender for the Hennessy Gold Cup at Newbury on Saturday.
The anticipated quick conditions ruled Paul Nolan's Joncol out but the Noel Meade-trained Muirhead does make the journey, although the Munster National winner will have to improve on his most recent outing at Ascot.
Leading ante-post hopes Aiteen Thirtythree and Great Endeavour also feature among 18 declared runners. The former has had the prestigious handicap as his long-term objective for much of his career and lines up following a highly encouraging second behind Somersby at Kempton.
His trainer Paul Nicholls also saddles top-weight Neptune Collonges, the mount of Harry Derham, and Michel Le Bon, who will be ridden by Noel Fehily on his first start since winning at this meeting two years ago.
Great Endeavour, trained by David Pipe, is bidding for a big-race double having won the Paddy Power Gold Cup at Cheltenham just a fortnight ago. Pipe's father Martin saddled Celestial Gold to win both races in 2004.
Two of last season's most exciting novice chasers in Wayward Prince and Wymott both take their chance, while Planet Of Sound is one of three runners for Philip Hobbs, along with Fair Along and Balthazar King. Other interesting contenders include Beshabar, Sarando, Carruthers and The Giant Bolster.