Willie Mullins' superstars Faugheen and Annie Power feature in a 47-strong entry for the Sun Bet Stayers' Hurdle at Cheltenham on March 16.
Mullins, who has yet to win the race, is responsible for 10 of the 19 Irish-trained entries.
Heading the ante-post market is Harry Fry's Unowhatimeanharry, winner of the Albert Bartlett Novices' Hurdle at the big meeting 12 months ago. Fry's ace took his unbeaten run to seven when beating Neil King's Lil Rockerfeller in the Long Walk Hurdle at Ascot last month.
Unowhatimeanharry's owner JP McManus has six entries in total. They also include 2014 scorer More Of That (Jonjo O'Neill), former Champion Hurdle hero Jezki (Jessica Harrington) and the Alan King-trained Yanworth.
Other high-profile contenders include 2015 winner Cole Harden (Warren Greatrex) and the Nigel Twiston-Davies-trained pair of Ballyoptic and The New One.
Another in contention is American challenger Rawnaq, formerly Irish-trained but now based with Cyril Murphy in Maryland.
The 10-year-old is going for a $500,000 bonus after defeating the Mullins pair of Shaneshill and Nichols Canyon in the three-mile Grade One Calvin Houghland Iroquois Hurdle, part of the first Brown Advisory Iroquois Cheltenham Challenge, at Percy Warner Park, Nashville, on fast going in May.
Rawnaq followed up his Iroquois Hurdle success with victory at Far Hills in October, when partnered by Ruby Walsh, and was second on his latest start in the Colonial Cup in November.
Murphy's gelding was previously trained in Ireland by Matthew Smith and already has experience at the Festival, having finished third in the 2015 Brown Advisory & Merriebelle Stable Plate over fences. He was also third in 2013 Greatwood Hurdle at the Open fixture.
Murphy said: "It is so far so good with Rawnaq. After he ran in November, we left him alone for a month and then started to pick him up again before Christmas.
"He did a piece of work last week and did another bit on Tuesday, and everything seems to be moving in the right direction for us.
"Rawnaq has been very solid. We bought him hoping he could be a Grade One horse but to go and do what he did last year and win two of them was great.
"He got beat the last day, which was disappointing for everybody, but in hindsight I think the ground was even firmer than we wanted. He just didn't have a cut at the fences.
"Ruby Walsh rode him in October and was impressed. He made himself available to us after Jack Doyle got injured and that said enough to me as he was behind us on Nichols Canyon in the Iroquois.
"I asked Ruby if he felt we could finish in the first four or five in Cheltenham and he said he would not put us off chasing the bonus because it is an open year in the stayers' division.
"The horse has run well over fences and hurdles at Cheltenham, so we know the track doesn't hold any fears. He is not ground dependent either as he won a good race on testing ground in Ireland.
"At the moment, the plan is to leave here either on February 3 or February 6 to arrive in England the following day. It is a 12-hour drive from our place to Huntsville airport in Alabama, then he has a direct flight to Stansted and finally a road trip to Neil Mulholland's where he will be based. You are looking at about 36 hours door to door.
"I worked with Neil Mulholland for a period of time at Nicky Henderson's. We lost contact in the interim but we got back in contact through an existing owner of his who lives and follows the racing out here. Before Nicky's, I was with Sir Mark Prescott for four years and then a conditional jockey with Bill Turner for four years. I rode 13 winners from about 200 rides.
"If everything goes right, the hope at the moment is to give Rawnaq a prep race in the National Spirit Hurdle at Fontwell on February 26.
"Jack Doyle is going to ride him. He won on him in his first two starts last year and would have ridden him in his last two starts but for getting injured. It was always the plan for Jack to ride him if he was available because he obviously knows the horse and has experience around Cheltenham."
