Al Kazeem will face six rivals as he goes in search of a third successive victory at the highest level in Saturday's Group One Eclipse Stakes at Sandown.
The five-year-old has won his past four races including the Tattersalls Gold Cup at the Curragh and the Prince Of Wales's Stakes at Royal Ascot at his past two starts.
Those last two successes came with triple Classic winner Camelot behind him, but he will be absent with trainer Aidan O'Brien taking the Roger Charlton-trained Al Kazeem on with two new challengers.
Mars will represent the three-year-olds having run with credit in the Guineas and the Derby. He will be ridden by Ryan Moore while stable jockey Joseph O'Brien will ride Declaration Of War, an impressive winner of the Queen Anne at Royal Ascot.
Al Kazeem just reeled in the William Haggas-trained Mukhadram at Ascot and the runner-up will be there for the rematch.
Some four lengths behind that pair was John Gosden's filly The Fugue, who was having her first run of the season. She is expected to strip much fitter but no filly has won the Eclipse since Kooyonga in 1992.
German challenger Pastorius adds further interest having won the Prix Ganay earlier in the season and Clive Brittain's Miblish completes the field.
Charlton has been delighted with Al Kazeem since his Ascot win and says the signs are that his charge has recovered well from his exertions.
"I've been very pleased with him. You can never tell when a horse has had a tough race as to how quickly they will recover, it is not an exact science," Charlton told At The Races.
Sponsors Coral make Al Kazeem their 15-8 favourite with Declaration of War and the Fugue at 4-1.