The Ballydoyle handler has saddled a record 11 winners of the Group Three contest, with subsequent Epsom Derby heroes Galileo (2001) and High Chaparral (2002) among those on the roll of honour, as well as the four-times Gold Cup winner Yeats.
This year O’Brien is represented by Nelson, Delano Roosevelt and The Pentagon, who finished first, second and third respectively in last month’s Ballysax Stakes over the same course and distance.
Dermot Weld has a pretty decent record in the Derrinstown himself having saddled eight previous winners and he relies on Hazapour, who makes his first appearance since October.
The Ger Lyons-trained Lethal Steps, Mick Halford’s Platinum Warrior, Jessica Harrington’s The King and Theobald from Jim Bolger’s yard complete the eight-strong field.
O’Brien fires two bullets at the Derrinstown Stud 1,000 Guineas Trial, with the highly-rated Magical joined by stablemate Ballet Shoes.
Weld has entered the exciting Leopardstown maiden winner Chiara Luna and Willie McCreery saddles impressive Salsabil Stakes winner Mary Tudor.
The Group Three Amethyst Stakes looks another strong heat, with five of the seven runners rated above 100.
Lyons runs both Brendan Brackan and Tennessee Wildcat, while Tom Hogan’s stable stalwart Gordon Lord Byron is joint top-rated horse along with Bolger’s Tribal Beat.
The unbeaten and unexposed Zihba is a fascinating contender for Fozzy Stack, with Johnny Murtagh’s True Valour and Jessica Harrington’s Pincheck the other runners.