The three-year-old will be taking on the boys for the first time, having been successful against older fillies and mares in the Group 1 Matron Stakes at Leopardstown in early September. The Matron Stakes marked a third straight Group 1 victory for the filly, who won the Irish 1000 Guineas and the Coronation Stakes at Royal Ascot in June.

In an interview with Sky Sports Racing, Dermot Weld said: "It's pretty clear the filly herself has progressed from each of her Group Ones wins, I'm delighted with her and we want to run – but I do have to put in the caveat that she's shown excellent speed on fast ground.

"She's also won on soft ground and she's a very adaptable filly, but I do have to advise that if the ground came up very heavy, she's not a big filly and it would cause concern.

"She's a brilliant filly and she will handle soft ground well, but I'm concerned about the weather forecast for that part of England, especially Friday night into Saturday.

"She will definitely travel over, [but] she is racing against some of the best colts in Europe and that [ground] is a concern."

The Breeders' Cup has been touted as a possible option for a couple of the leading contenders at Ascot on Saturday, should the ground prove too soft.

"We haven't even discussed that [the Breeders' Cup] because it would be wrong to do so. Let's concentrate on Saturday and let's hope to be there.

"Champions Day has always been a very good day for me. Fascinating Rock won the Champion Stakes, we won the fillies' and mares' race with Sapphire and the Long Distance Cup I've won a couple of times with Forgotten Rules and Rite Of Passage.

"Ascot itself as a track has been very good to me. I think I've trained 19 Group winners at the Royal meeting and my horses always run extremely well at Ascot.

"Tahiyra is in great form, I couldn't be happier with the filly, her final piece of work was excellent and her graph has gone the right direction throughout the year.

"I'm just very positive of a big run for Saturday."

Tahiyra is currently 5/2 shot for the Group 1 Queen Elizabeth II Stakes.