Christophe Soumillon will ride the favourite Tarnawa in the Prix de l'Arc de Triomphe on Sunday week.
Dermot Weld confirmed on Tuesday the decision has been taken to replace Colin Keane with Soumillon in Europe's premier all-aged race.
Keane, the season’s leading rider in Ireland, has partnered Tarnawa in both her starts this year including when an unlucky runner-up to St Mark’s Basilica in the Irish Champion Stakes 10 days ago.
However Soumillon, who rode the mare to win both the Prix Veremeille and the Prix de l’Opera at Longchamp last autumn, will be back on board for the Arc.
The Belgian jockey is the retained rider in France to Tarnawa's owner, the Aga Khan.
“Christophe Soumillon will ride Tarnawa in the Prix de l’Arc de Triomphe. He knows the filly well and he is his highness’ retained jockey in France,” Weld said.
Soumillon, twice an Arc winner for the Aga Khan on Dalakhani (2003) and Zarkava (2008,) had been set to maintain his partnership with Tarnawa at the Breeders Cup last November only to test positive for Covid-19 on the eve of the meeting.
Weld turned to Keane who was in Keeneland to ride Siskin and the Irishman produced Tarnawa to win the mile and a half Turf race. It was a first Breeders Cup victory for both Keane and Weld.
The partnership was formalised at the start of this season with Keane riding extensively for Weld when not required by Ger Lyons.
It has paid off with Keane on course to break Joseph O’Brien’s 2013 record of 126 winners in a season.
However missing out on Tarnawa in the Arc, for which she is a general 11-4 favourite, is a rare reverse this season for the 27 year-old Irish jockey.