Zara Phillips will be named in the Great Britain eventing team for London 2012, Press Association Sport understands.
It is believed that 31-year-old Phillips, the Queen's granddaughter, has gained selection alongside three Olympians - William Fox-Pitt, Mary King and Tina Cook - plus last year's Badminton runner-up Piggy French.
Nicola Wilson, who has helped Britain win world and European team gold medals in the last three years on her brilliant cross-country exponent Opposition Buzz, is thought to be among those who has missed out.
A three-strong selection panel of Ian Stark, Mandy Stibbe and Angela Tucker made their final deliberations following Sunday's Equi-Trek Bramham International Horse Trials in Yorkshire.
Phillips, the 2006 individual world champion, delivered an eye-catching display aboard High Kingdom, finishing third in the CIC three-star section behind world number one Fox-Pitt and New Zealander Andrew Nicholson.
Bramham was effectively a final selection trial before London, and took on added significance after wet weather caused major pre-Olympic competitions at Badminton and Chatsworth last month to be called off.
Phillips will emulate both her parents by competing at Greenwich Park next month.
Her mother, the Princess Royal, evented at the 1976 Montreal Olympics, while her father Captain Mark Phillips won team gold at the Munich 1972 Games, and then silver in Seoul 16 years later.
Phillips' world championship-winning horse Toytown was formally retired last year, and she has struggled to make a consistent impact since then.
But she has always rated High Kingdom highly, and will now get the chance to prove it, with her Olympics selection coming in the Queen's Diamond Jubilee year. Phillips recorded a personal best dressage score of 43.2 penalties on High Kingdom on Sunday, then jumped clear in the showjumping and cross-country.