The six-year-old, who is rated 164p by Timeform, won at last month's Cheltenham Festival for the second year running with a brilliant performance in the Jewson Novices' Chase, and is now the ante-post favourite for the Cheltenham Gold Cup next March, trading at ([6.6]).
He steps up to Grade One level for the first time, and also steps up in distance.
"I'm happy he's in good shape and I wouldn't be worried about the ground for him, he should be fine," said Mullins.
"We're looking forward to trying him over this trip and running him in a Grade One. Hopefully he'll take the step up."
Next best on the Timeform ratings is Declan McNamara's Mossey Joe, a dual winner last May.
He has not been sighted since suffering injury on his final start at Down Royal in June, however, and is trainer is just hoping his star turn comes home safe and sound.
"He's as good as I can have him without a run, but I would have preferred to have got a run into him beforehand. He will come on for it," said McNamara.
"He picked up a hock injury in Down Royal and he had to have a couple of operations to fix it. The vets only gave him a 50-50 chance of coming back and racing again, so it's great just to have him back.
"He seems in good shape and it's his last chance to run in a novice race.
"Fingers crossed he gets round and comes home safe and sound. Hopefully he might pick a bit of prize-money as well.
"I haven't really thought past tomorrow but if all goes well and he's sound afterwards, we'll keep him going as he's a good ground horse."
Frisco Depot comes here in good form, having finished second to the prolific Flemenstar before winning at Limerick.
His trainer Dessie Hughes has no concerns about the testing conditions.
"It's the end of the season so we thought it would be worth having a go. I think he deserves a crack at it," said Hughes.
"He handles soft to heavy ground all right and he's a horse that stays well.
"He has some good form in the book and I was very happy with him the last day, so fingers crossed he can run well."
Talented mare Shop DJ ran well behind Quevega in the David Nicholson Mares' Hurdle at Cheltenham, but disappointed back over fences at Fairyhouse last time.
Trainer Peter Fahey admits the ground will not be in her favour at Punchestown but is still hopeful she can run into the money.
"She actually came out of her last run in Fairyhouse really well," said Fahey.
"We just put that slightly disappointing run down to the ground and I know it's going to be similar tomorrow, but we're probably only running for the places anyway as Willie's horse is obviously going to be very hard to beat.
"She is rated a good bit lower over fences than hurdles but I think that's probably because she's never really got her ground over fences yet. We've just been a bit unlucky on that score really.
"Hopefully she'll give a good account of herself and pick up a bit of prize-money and then she'll probably get a break."
Completing the five-runner field is Ordinary Man, a winner at Tramore little over a week ago.
The other feature race from Punchestown on Tuesday afternoon is the Champion Chase, a race that sees Sizing Europe take on Big Zeb, the former trading at ([1.40]) favourite on Betfair.
Sizing Europe is considered 7 lb superior to the Colm Murphy-trained gelding in terms of Timeform figures and he is fully expected to land the prize.