Joseph O'Brien and Richard Hughes, reigning champion Flat jockeys in Ireland and Britain respectively, have been granted jumps licences to ride in the Weatherbys Champion Bumper at Cheltenham on Wednesday.
The Irish Turf Club approved O'Brien's application, while the British Horseracing Authority has given Hughes permission to compete.
O'Brien is set to partner recent Leopardstown winner Shield for his father Aidan, with Hughes aboard Sgt Reckless for trainer Mick Channon.
Although Hughes has been in action at Cheltenham in the past and is due to help out his father Dessie at the meeting, it will be a new experience for O'Brien.
"He has been approved to ride in the bumper. He'll have an Irish National Hunt licence for a year," said Denis Egan, chief executive of the Irish Turf Club.
BHA spokesman Robin Mounsey added: "Hughes was granted his jumps licence on Thursday to ride."
Michael Channon junior, Channon's son and assistant, said: "As long as Hughesie has got everything through he will be riding. It's hard on Dominic (Elsworth), who has done nothing wrong, but it is a Flat race and Hughesie is the champion jockey.
"Of course, if Hughesie wasn't riding the ride would be Dominic's."