Michelle Payne has arrived in England ahead of her ride on Kaspersky in the Queen Anne Stakes, the first race of the Royal Ascot meeting.
While she has been cleared to ride the Jane Chapple-Hyam-trained six-year-old on Tuesday, there is still confusion about whether her visa allows her to ride other horses in their work or in races.
Despite having ridden in the UK in the past, Payne incurred an unexpected hitch over her visa requirements and is in contact with the British Horseracing Authority to clarify the situation.
"I think her visa only permits her to ride Kaspersky," Chapple-Hyam said.
"We're going to call the BHA and see what the score is."
Payne, who made history in 2015 when she became the first female jockey to win the Melbourne Cup aboard Prince of Penzance, will be based in Newmarket with Australian-born Chapple-Hyam.
Kaspersky will be one of the outsiders in the Group One race over the straight mile (1600m) for which Lockinge winner Ribchester is the short-priced market leader.
Formerly trained by Endo Botti, Kaspersky made his debut for Chapple-Hyam when fifth in the Listed Paradise Stakes at Ascot and was second behind Another Touch in a handicap at Nottingham last time out.
"The horse is absolutely fine. We're a 40-1 shot but I think we'll run better than our price suggests," Chapple-Hyam said.
Kaspersky, who is a Group Two winner in Italy and Germany and was placed at the top level last season, has been bought by Australian interests.
The plan is for Kaspersky to travel to Australia later this year to be trained by Payne, who holds a dual licence.
The Emirates Stakes during the Melbourne Cup carnival in November will be among his targets.