The daughter of Galileo has proved to be a cut above other three-year-old fillies this season, chalking up four Group One victories from a mile to a mile and a half.
She holds an entry in the Coolmore Matron Stakes, for fillies and mares, on the same card, but the Champion Stakes, in which she could take on dual Derby hero Harzand and French Derby winner Almanzor, is tempting.
"She'll run in either the Matron or the Champion Stakes. The lads (owners) will make the decision closer the time, but it's very possible she'll go to the Champion Stakes," O'Brien told At The Races.
"We're very happy with her. She's had a nice bit of time since her last run.
"Her work is very good and physically she's doing very well."
O'Brien has a potential headline-maker on day two of Irish Champions Weekend in Churchill, who is being geared up for the Group One Goffs Vincent O'Brien National Stakes at the Curragh.
The Galileo colt has progressed at a rate of knots since being beaten on his debut, having won the Listed Chesham Stakes, the Group Three Tyros Stakes and the Group Two Futurity Stakes.
"We're looking forward to the National Stakes with him. We think it will suit him well and physically he's doing very well," said O'Brien.
"We've thought he would be a Guineas horse. He's a horse with a lot of speed. He's a big powerful individual. He's built like a big miler so I'm no sure how much more he'll stay.
"We think he might get the mile and a quarter but you wouldn't be sure about the mile and a half. We're very happy with him."
Listed - East Cape Guineas
G3 - Kings Cup
G2 - Resource Recycling Superstars Championship
G3 - Lamb & Hayward 4&5yo Trotting Championship
G2 - Storer Motors Nz Trotting Oaks