Westover will be partnered by Colin Keane in the Dubai Duty Free Irish Derby at the Curragh on Saturday.

A fast-finishing third in the Derby at Epsom three weeks ago after enduring a troubled run, the Ralph Beckett-trained Westover has been at the head of ante-post lists for the Irish equivalent ever since.

What connections did not envisage, however, was a curveball from Aidan O’Brien, who revealed on Monday that it was “very possible” that Oaks winner Tuesday would be added to the field to take on the colts.

With her participation now confirmed, the daughter of Galileo, who was placed in the 1000 Guineas and the Irish 1000 Guineas prior to her narrow defeat of Emily Upjohn at Epsom, will bid to become the first filly to win the Irish Derby since the Frankie Dettori-ridden Balanchine in 1994.

Barry Mahon, general manager of Ireland and European racing for Westover’s owner-breeders Juddmonte, said: “Westover is good. He did his last bit of work on Monday morning and Ralph and the team were happy, so everything seems set for Saturday.

“I don’t know what way the bookies will chalk it up with Tuesday in the race. She’s a top class filly who has been placed in two Guineas and won an Oaks and is bred in the purple, so she’s gong to be a formidable opponent, especially with the 3lb allowance.

“I think her inclusion is going to guarantee a very good race.”

Rob Hornby has been on board Westover on his two previous starts this season, but Keane will take over this weekend, with connections hoping to make the most of his local knowledge.

Mahon added: “Rob Hornby is an integral part of the team in Ralph Beckett’s, has done a wonderful job with Westover and I thought he gave him a beautiful ride in Epsom.

“Our decision is purely down to Colin’s experience and experience of the Curragh and Curragh classics. What better man than a three-time Irish champion jockey who has won an Irish 2000 Guineas and an Irish Oaks at the Curragh to get on board?

“He knows the track inside out and hopefully that will be a help to Westover. We just felt, for this race race anyway, that he’s an able deputy.”

Westover and Tuesday are among 16 possible runners in the Ireland’s premier classic following the confirmation stage, with the latter unsurprisingly the only filly in contention.

Westover is set to be joined on the trip from Britain by the David Menuisier-trained Lionel, who has had this as his target since winning last month’s Cocked Hat Stakes at Goodwood.