“Both Clan Royal and Joss Naylor will run,” said O’Neill. “Paul Carberry will ride Joss and Liam Cooper will ride Clan Royal.”

There has been a slew of sizeable bets in Ireland this week for the J. P. McManus-owned Clan Royal, who is currently 12-1 third favourite with Paddy Power for the £600,000 (€898,066) Aintree extravaganza, having been clipped in from 20-1 generally 10 days ago.

O’Neill added: “There have been no problems with either of them and both are in great form, touch wood. I am very happy with them.”

The French-bred Clan Royal, who looks well weighted on 10st 2lb, holds a 100% record at Aintree, having won last season’s Martell Cognac Sainsbury’s Topham Chase and this term’s sole start in the Tote Becher Chase, both under Saturday’s big-race pilot.

Neither horse has been seen out since November.

Unraced since a narrow second to Strong Flow in the Hennessy at Newbury, Joss Naylor was prominent on the betting lists for the Welsh National, the Red Square Vodka Gold Cup and the recent William Hill NH Chase at the Cheltenham Festival, only to miss all three races.

Despite his non-appearance, the nine-year-old has attracted plenty of attention this winter and his owner, Darren Mercer, is soon to face a disciplinary inquiry at the Jockey Club.

Yet O’Neill intimates the horse, set to shoulder 10st 8lb, may yet make the headlines for all the right reasons.

“You’d have to say Joss was the better class horse of our two National runners. It is just that while the other fella has handled the fences really well, Joss hasn’t tackled them yet,” admitted O’Neill.

“They both have a decent weight and I am sure Aintree will provide perfect ground. Good ground is what we’ll expect to find, though to be honest, both of them wouldn’t mind a drop of rain. As long as the ground isn’t fast, we’ll have no complaints.

“We are just very lucky to have two horses that are both good enough to run there.”