The filly Enable, to be ridden by Frankie Dettori, will bid to make history on Sunday in the Prix de l'Arc de Triomphe at Longchamp.
No horse has ever won three runnings of the European Championship for flat horses, and the John Gosden trained superstar will bid to do that from stall nine in Paris.
One quirk is that only one runner from stall nine has won the Arc in the last 55 renewals of the race. That was Urban Sea back in 1993.
Champion trainer Aidan O'Brien holds two cards in the pack, Japan, who will be the mount of Ryan Moore, and Magical, to be ridden by Donnacha O'Brien. O'Brien has won the race twice before.
Enable is the odds on favourite for the one-mile-four-furlong test and the going will be soft on Sunday for post time at 3.05.
The field is completed by French King, Waldgeist, Ghaiyyath, Kiseki, Blast Onepiece, Fierement, Nagano Gold, Soft Light and French Derby winner Sottsass.
The last horse to go back to back was Alleged in 1978.
Enable won her first Arc at Chantilly, before hanging on close home at Longchamp twelve months ago. She has won 13 of her 14 races in the famous green, white and pink silks of owner Khalid Abdullah.