The 58-year-old is leading the engagement at the Buckingham Palace gardens in London. Clad in a blue shirt and matching tie, he shook hands with Strictly star Johannes Radebe.
Royal Windsor Horse Show tickets will go on sale at 9am tomorrow (Thursday, 6 May).
Five-star showjumping returns to Royal Windsor this year, featuring a total prize fund of more than €500,000 (£431,000) and finishing with the Rolex grand prix on Sunday, 4 July.
There will also be the usual high-profile showing classes, international driving and endurance, but no dressage this year.
Membership tickets, limited to 500 members plus guests, and general entry tickets will both be available to buy from tomorrow (6 May).
Organisers have said they will allow up to 4,000 spectator tickets on each of the four days of the show, adhering to the Government Covid-19 guidelines as of 17 May.