Piggy French will ride her Olympic Test event winner DHI Topper W in the eventing at London 2012.
Leicestershire-based French was last week named in Great Britain's five-strong eventing team for Greenwich Park alongside William Fox-Pitt, Mary King, Tina Cook and Zara Phillips.
And it has now been confirmed that French will be aboard Topper, rather than Jakata, the horse on which she finished runner-up behind New Zealander Mark Todd at Badminton last year. Topper has crucial experience of the challenging Greenwich Park terrain, emerging victorious in the Test event almost a year ago ahead of Pippa Funnell and Michael Jung.
"He may be a young horse, but he has already proven himself talented and suited to Greenwich, and then going on to win the Blenheim CCI three-star," Britain's eventing performance manager Yogi Breisner said.
Funnell, meanwhile, has been named among 10 reserve combinations for the eventing team with Mirage D'Elle.
The others are Fox-Pitt's Burghley and Kentucky four-star winner Parklane Hawk, plus his recent Bramham CCI three-star champion Neuf des Coeurs, King (Kings Temptress), Sarah Cohen (Treason), Laura Collett (Rayef), Francis Whittington (Sir Percival III), Polly Stockton (Westwood Mariner), Lucy Wiegersma (Simon Porloe) and Nicola Wilson (Opposition Buzz).
Nominations, meanwhile, have been announced for the showjumping and dressage disciplines, from which four-strong teams will be named.
The showjumping nominations are Scott Brash (Hello Sanctos and Intertoy Z), Peter Charles (Murka's Nevada and Murka's Vindicat W), Nick Skelton (Carlo and Big Star), Tina Fletcher (Hello Sailor), Will Funnell (Billy Angelo and Billy Congo), Ben Maher (Tripple X III), Tim Stockdale (Fresh Direct Kalico Bay), John Whitaker (Maximillian), Michael Whitaker (GIG Amai and Viking) and Guy Williams (Depardieu Van T Kiezelhof).
In dressage, where Britain are strongly backed for team and individual Olympic medals, Carl Hester, Charlotte Dujardian and Laura Bechtolsheimer lead the nominations. All three were members of Britain's European title-winning team last August, and the trio are currently ranked among the world's top five.
The dressage nominations comprise Hester (Uthopia), Dujardin (Valegro), Bechtolsheimer (Mistral Hojris and Andretti H), Henriette Anderson (Louis D'Or), Hannah Biggs (Weltzin), Nikki Crisp (Pasoa), Richard Davison (Hiscox Artemis), Michael Eilberg (Half Moon Delphi and Marakov), Emile Faurie (Elmegardens Marquis), Judy Harvey (Fitzcerraldo), Emma Hindle (Diamond Hit) and Gareth Hughes (DV Stenkjers Nadonna).