Hot favourite Hurricane Lane heads a final field of 10 for the Cazoo St Leger at Doncaster.
Winner of the Irish Derby and Grand Prix de Paris on his last two starts, the Charlie Appleby-trained Hurricane Lane is odds-on to make a successful transition to 14 furlongs in the final British Classic of the season on Saturday.
Ottoman Emperor will be seeking a fifth successive win for Johnny Murtagh as he switches up to Group One company for the first time.
He won a Cork maiden in April and has been on a rapid upwards trajectory since, landing a Gowran handicap in June before adding another win at Navan and successfully moving up to Group Three level to win the Gordon Stakes at Goodwood in July.
Ottoman Emperor is one of six contenders from Ireland – with Aidan O’Brien sending the supplemented High Definition, plus Interpretation, Sir Lucan and The Mediterranean.
High Definition was an early Derby favourite but has endured a disappointing campaign so far, most recently finishing a well-beaten sixth in the Great Voltigeur at York – in which The Mediterranean was runner up, with Sir Lucan fourth.
Interpretation has won his last three, including the Listed Vinnie Roe Stakes last time, in which the reopposing Fernando Vichi was second for Donnacha O’Brien.
Frankie Dettori will ride High Definition, with Hollie Doyle aboard Interpretation. James Doyle has been booked for Sir Lucan and Wayne Lordan partners The Mediterranean.
Derby runner-up Mojo Star has another shot at Classic glory, with Richard Hannon having sent him to Newbury last month for a confidence-boosting win in a 12-furlong maiden – the first victory of his five-race career.
Youth Spirit finished fourth behind Ottoman Emperor at Goodwood and third in the Voltigeur last time. He runs for Andrew Balding, who so nearly won the race last year when his Berkshire Rocco was beaten just a neck.
Voltigeur fifth Scope, who is trained by Ralph Beckett, completes the Leger line-up.