Coolmore runners headline both top-level contests May 27 at the Curragh, with Cliffs Of Moher facing four rivals in the Tattersalls Gold Cup (G1) before Happily squares off against 12 in the Tattersalls Irish One Thousand Guineas (G1).
Cliffs Of Moher will make the third start of his 4-year-old campaign. After finishing last in the Toals.com Bookmakers Alleged Stakes (G3) at Naas, he followed with a win at the same track in the Coolmore Camelot Irish EBF Mooresbridge Stakes (G2).
The son of Galileo only won once at 3 in a season highlighted by a second-place finish in the Investec Derby (G1) at Epsom. Ryan Moore will ride for trainer Aidan O'Brien, who is seeking a record seventh win in the 10 1/2-furlong Gold Cup. O'Brien last won the race in 2012 with So You Think.
O'Brien also saddles Lancaster Bomber, who ran third last week in the Al Shaqab Lockinge Stakes (G1) over a mile at Newbury. Seamie Heffernan will maintain his partnership with the War Front colt.
"We're very happy with Cliffs Of Moher's win in the Mooresbridge Stakes at Naas last time. He came out of the race well, and we think a mile and a quarter suits him well," O'Brien said. "He'll also like the fast ground, whilst Lancaster Bomber ran very well in the Lockinge, and we thought this would be a good time to step him up in trip."
Chief rival to Cliffs Of Moher figures to be Sheikh Mohammed Obaid Al Maktoum's Defoe. The Roger Varian-trained colt has won six of his last seven starts, including an impressive score in the Dunaden Jockey Club Stakes (G2) this month at Newmarket. The son of Dalakhani will be ridden by Andrea Atzeni.
Varian will walk the course on Sunday before deciding whether to run Defoe.
"Defoe's participation will depend on how quick the ground is. He's certainly earned the return to group 1 company after winning at group 2 and group 3 this season," the trainer said. "I don't think the drop back from a mile and a half would inconvenience him on a track like the Curragh. He's training nicely and would have a very live chance on form, but I wouldn't want to compromise his season by running him on an unsuitable surface. So a final decision about his participation will be made at the last minute."
Three races after the Gold Cup, the classic fillies will take center stage in the Guineas over a mile.
O'Brien, bidding for a record eighth win in the race, will saddle four: Happily, Clemmie, Could It Be Love, and Most Gifted. O'Brien won the race last year with Winter.
Moore will have the mount on Happily, who kicked off her 2018 season with a third-place finish in the QIPCO One Thousand Guineas (G1) at Newmarket. The daughter of Galileo was a dual group 1 winner at 2, taking out the Moyglare Stud Stakes (G1) before beating the boys in the Qatar Prix Jean-Luc Lagardere (G1) at Chantilly on Arc day.
"We think Happily has improved since Newmarket and that the Curragh mile will suit her well," O'Brien said. "She's a filly who will stay further. She's in good form, and we're very happy with her."
O'Brien's other big player is Clemmie, a winner of the Juddmonte Cheveley Park Stakes (G1) at Newmarket last fall. Sunday's race will be her season debut.
"Clemmie is an exciting filly. She's been working well and is just ready to start off. We're hoping she runs well, but there should be plenty of improvement in her between now and Royal Ascot."
Another by Galileo, she will be ridden by Heffernan.
Four of the last seven winners in this race ran in the English guineas beforehand. The only other runner besides Happily from that contest is Godolphin's Soliloquy. Trainer Charlie Appleby's Dubawi filly finished sixth at Newmarket after running away with the Lanwades Stud Nell Gwyn Stakes (G3) at the same track in April. William Buick will retain the ride.
"Soliloquy has come out of Newmarket very well, and if she reproduces the Nell Gwyn performance, it will obviously make her very competitive," Appleby said. "We did change her running style in the One Thousand Guineas, which probably didn't suit her in hindsight. She goes there in good form and has no excuses this time around. I'm not going to say we'll be making the running, but we may make more use of her, as William said holding her up was taking her out of her stride."
Other notable contenders include Who's Steph, Alghabrah, and Chiara Luna. That trio finished 1-3-4 in the Derrinstown Stud One Thousand Guineas Trial (G3) May 13. Qatar Racing Limited's Lightening Quick, who took out the Coolmore Mastercraftsman Irish EBF Athasi Stakes (G3) in her season debut, has been moved to trainer Johnny Murtagh after a well-publicized split between her owner and former handler, Ger Lyons.