Donnacha O'Brien favouring French Oaks for Irish Guineas second Fancy Blue

Donnacha O'Brien could trump his father Aidan to a breakthrough success in the Prix de Diane next month as he's strongly considering a tilt at the Group 1 with exciting Irish 1,000 Guineas runner-up Fancy Blue.

The Investec Oaks remains a possibility for the daughter of Deep Impact after she enhanced her reputation despite forfeiting her unbeaten record this month, but O'Brien is leaning towards the French equivalent over 1m2½f for his stable star a week on Sunday.

"We're not 100 per cent sure at this stage but she's working towards that weekend, with the Prix de Diane scheduled for the day after Epsom," said O'Brien, whose record-breaking father has yet to win the fillies' Classic. "It'll be one or the other for her."

He added: "If they got a lot of rain at Epsom which would cause the field to cut up a little bit, we could think about bringing her back to there, but at the minute the plan is to go to the Diane."

Donnacha O'Brien on Fancy Blue: 'She's in great form since the Curragh and has only done one gentle piece of work'Credit: Patrick McCann

Fancy Blue, who is also entered in the Juddmonte Irish Oaks, Kilboy Estate Stakes and Tattersalls Gold Cup, was cut from a general 25-1 to 10-1 for Epsom glory following her Curragh second.

"It was a very good run from her at the Curragh," O'Brien said. "We thought she wanted further and she did end up looking like that.

"She was a little bit off the bridle early and came home really well, so we're going to step her up in trip."

Fancy Blue: finished second to Peaceful in the Tattersalls Irish 1,000 GuineasCredit: Caroline Norris

He added: "She's in great form since the Curragh and has only done one gentle piece of work. She's moving well and everything's good with her."

The last Irish-trained runner to contest the Prix de Diane was Aidan O'Brien's Happily, who finished fourth to Laurens in 2018.

Keep up to date on the must-have news, tips, photos and more by following the Racing Post across all social channels