Her Royal Highness Princess Sirivannavari Nariratana Rajakanya will compete in the inaugural International Equestrian Federation (FEI) Asian Championships in Pattaya in December.
The Princess has appeared in a TV commercial for the event, to be held at the Thai Polo & Equestrian Club in Pattaya from Dec 1-8.
"I am very honoured to represent my country as a rider. Every time I see my name and the Thai flag, it's like, wow!" she said.
"I train six days a week. Any kind of sports makes you strong but this is more soulful."
The Princess added: "During December we are going to host the FEI Asian Championships.
"It is the first time in history that we will be hosting the championships. It's time for us to shine and to show the world what we can do."
The FEI expects athletes from about 15 countries and more than 100 horses to take part in the event which features three disciplines -- dressage, show jumping and eventing.
Although the Princess is now a world-renowned fashion designer, she has been a successful athlete.
She was a silver medallist in the dressage team event at the 2017 SEA Games in Malaysia.
As a badminton player, the Princess won gold in the women's team event at the 2005 SEA Games in the Philippines.
Meanwhile, the FEI said the equestrian facilities in Pattaya are of the highest standard with approximately 250 acres of land providing stables for over 250 horses, a veterinary clinic, numerous sand and grass arenas as well as a cross country track.
The Thai Polo & Equestrian Club is a "wonderful multi-functional equestrian facility" and has been a remarkable host in the past for important events, it said.