O’Brien has been handed the ride on Beyond Brilliance, one of five contenders in the race trained by her father, who chases a fourth win in the race and a first since Moonstone made it three Irish Oaks wins in a row for the trainer in 2008.
The 7lb claimer has built a good relationship with her Classic ride, who runs in the silks of her mother Anne-Marie, this year, partnering the filly in all but one of her ten starts this season and winning twice.
On her latest run, Beyond Brilliance finished a close third to stablemate Palace in a Listed race at Killarney on July 14.
O’Brien partnered her first winner at the age of 16 when Fairylike, trained by Aidan and owned by Anne-Marie, landed an apprentice handicap at Dundalk in February of last year.
She has ridden nine winners to date — five last year and four in 2014.
Meanwhile, Nina Carberry will be continuing her racing education by joining Aidan O’Brien’s stable as a work rider.
Ireland’s most successful female jockey, who has been champion amateur and won Cheltenham Festival races as well as the Irish Grand National, became racing assistant to Noel Meade last year.
Carberry said: “It’s great, I’m looking forward to it. I just thought it was a really good opportunity to learn a bit more about the Flat racing scene.
“Noel’s been very good about it. I’ll still be riding for him, and saddling up horses for him, anyway.”