Frankie Dettori has been booked to ride New Graduate, the general 5-1 favourite for the Royal Hunt Cup at Ascot on Wednesday.
The James Tate-trained colt, supported in from 10-1 in the build-up to the royal meeting, will be partnered by Dettori for the first time.
Owned by Saeed Manana, New Graduate has been ridden by David Allan on his last two starts.
Tate said: "We had a discussion about who should ride him and we know Frankie Dettori is arguably one of the best jockeys in the world and is particularly good at Ascot. We are fortunate he is available to ride the horse."
New Graduate has not finished outside the top two in four starts and was last seen running out an impressive five-length winner at Ripon in April.
Dettori has won the mile handicap with Surprise Encounter (2001) and Invisible Man (2010).
PJ McDonald will stay on board Invincible Army, also trained by Tate, in Saturday's Diamond Jubilee Stakes, for which he is the general 11-4 favourite.
Ascot clerk Chris Stickels is expecting to change the going description on the straight course to 'good' on either Sunday or Monday. On Saturday afternoon the straight track was described as 'good to soft', with the round course 'soft, good to soft in places'.
Speaking on Saturday, Stickels said: "We've just had a small shower and might have a couple more today. There's proper moisture all the way through and it's just the top drying out really.
"If the forecast is correct and we don't get much more rain after today, I'd expect it'll change to good at some point tomorrow or Monday."
Looking ahead to what the going description will be when the royal meeting opens on Tuesday, Stickels added: "It's obviously difficult to predict, but I'd probably anticipate good ground for the straight course and good to soft on the round before racing on Tuesday.
"There isn't a massive amount of rain forecast and I wouldn't be confident of saying it will be good to firm, but there could be a bit of good to firm on the straight course."