The races have drawn entries of 42 and 64 respectively, with Thisthatandtother and Sunday's Leopardstown winner Kicking King heading the Arkle nominations.
Kicking King is one of 12 Irish entries and is set to renew rivalry at Cheltenham with the Dessie Hughes-trained Central House, second to Tom Taafe’s charge at Leopardstown.
Nicky Henderson, who has won the two-mile contest three times before, has put in Caracciola, Chauvinist, Lilium De Cotte, Nas Na Riogh, No Shenanigans and Non So.
As well as Thisthatandtother, Paul Nicholls, who took the race last year with Azertyuiop has also entered Bal De Nuit, Ladalko, Le Duc and Santenay.
Champion trainer Martin Pipe’s six Arkle entries include the highly-regarded Our Vic, who is set to make his chasing debut this week, last season’s Smurfit Champion Hurdle second Westender and Elite Hurdle victor Well Chief.
The Royal & SunAlliance Chase on March 17 sees Martin Pipe accounting for no less than 11 of those engaged.
There is a formidable 19-strong challenge from Ireland with possible raiders including 2002 Weatherbys Champion Bumper hero Pizarro, Direct Bearing and Emotional Moment.
Francis Crowley has entered Nil Desperandum but he is not certain to make the line-up after suffering a setback last week.