Tapestry has emerged a possible challenger for the Prix de l'Arc de Triomphe with Coolmore planning to pay a late entry to put her in Europe's most prestigious race.

The addition of Aidan O'Brien's three-year-old, who lowered the colours of Arc pre-post favourite Taghrooda in the Yorkshire Oaks in August, would pave the way for Ryan Moore to take the mount at Longchamp on Sunday.

"The plan is if she is in good order in the morning she will be supplemented and Ryan Moore will ride," Coolmore spokesman Richard Henry said.

The final chance to supplement for the Arc is on Thursday (Friday AEST) morning, when the filly's connections must pay 120,000 ($A180,000) to add her to the field.

Another piece of the Arc jigsaw has slotted into place with Frankie Dettori confirmed as the rider of the O'Brien-trained Ruler Of The World.

It had been feared the Italian, who missed the winning mount on Treve 12 months ago at Longchamp and has been replaced on the filly by Thierry Jarnet, would be forced to watch from the sidelines once again.

There was speculation over which jockey would get the nod on O'Brien's 2013 Epsom Derby winner, although three-times Arc winner Dettori had been in the saddle when he registered his victory in the Prix Foy.

Al Shaqab Racing, which retains Dettori, is a part-owner of the Galileo colt along with the Coolmore partners, and O'Brien's son, Joseph, had ridden him on his previous start in the Dubai World Cup.

O'Brien is also due to represented by Chicquita, the intended mount of Joseph O'Brien.