The eight-year-old French horse has been installed as favourite for the Group One Champion Stakes, the feature race on a day in which a record-breaking £4million prize money will be up for grabs.
Cirrus Des Aigles, drawn in stall nine, won the inaugural Champion Stakes three years ago, but was second to the legendary Frankel the following year and then Farhh 12 months ago over a mile and two furlongs.
Christophe Soumillon's mount was controversially denied a fourth consecutive victory when he was demoted to fifth place in the QNB Prix Dollar at Longchamp earlier this month on his return from injury, after being deemed to have interfered with Fractional and Planetaire.
Trainer Corine Barande-Barbe revealed that Cirrus Des Aigles, winner of the Coronation Cup at Epsom in June, is in good order ahead of a race that could see the French raider pass the £6million mark in prize money.
"I think he's on his way to being at his peak on Saturday," she said.
"There's still some strong horses in there. Noble Mission, he's a good horse. It's never easy."
Lady Cecil hopes Noble Mission can emulate his brother Frankel, who won this race on his final outing before being retired to stud two years ago.
"I couldn't be happier with him," the Newmarket-based trainer said.
"He did his last piece of work on Saturday and just loved it. Just to have a runner at QIPCO British Champions Day is wonderful but to have one in with a chance is a privilege and is not something to be taken lightly."
The Dermot Weld-trained Free Eagle is not a certain runner on ground that was described as heavy and soft in places on Thursday following rainfall throughout the week.
Nine horses were declared for the feature race, with Joseph O'Brien replacing Frankie Dettori on last year's Derby winner Ruler Of The World - trained by his father Aidan O'Brien.
Night Of Thunder, ridden by Richard Hughes, heads the market for the one mile Group One Queen Elizabeth II Stakes and trainer Richard Hannon is bullish over the three-year-old's chances.
Hannon said: “Night Of Thunder is in good form and has been moving very well.
"He ended up a bit further back than we had wanted in the Prix du Moulin which made life difficult so he did well to get so close to Charm Spirit.
"He will love the soft ground and his QIPCO 2000 Guineas victory is the best piece of form on offer as he is the only horse ever to have beaten Kingman."
Charm Spirit, Integral and Custom Cut will be among Night Of Thunder's rivals.
Estimate, the Queen's horse, has been declared for the British Champions Long Distance Cup, but will face strong opposition from the likes of Leading Light.
The British Champions Sprints Stakes, The Fillies and Mares Stakes and The Balmoral Handicap will also be contested on another strong card at the fourth Champions Day at Ascot.