Princess Eugenie’s Son August, 1, Makes His Royal Debut for Platinum Jubilee — in a Tiny Union Jack Sweater!

LONDON, ENGLAND - JUNE 05: Princess Eugenie of York, August Brooksbank, Jack Brooksbank, Birgitte, Duchess of Gloucester, Lord-Lieutenant of Greater London Ken Olisa during the Platinum Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Chris Jackson - WPA Pool/Getty Images) — LONDON, ENGLAND – JUNE 05: Princess Eugenie of York, August Brooksbank, Jack Brooksbank, Birgitte, Duchess of Gloucester, Lord-Lieutenant of Greater London Ken Olisa during the Platinum Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Chris Jackson – WPA Pool/Getty Images)

Chris Jackson – WPA Pool/Getty Princess Eugenie and August Brooksbank

August Brooksbank is getting into the Jubilee spirit with his first-ever royal appearance!

Queen Elizabeth’s great-grandson, 1, made his royal debut alongside parents Princess Eugenie and Jack Brooksbank at the Platinum Jubilee Pageant in London on Sunday.

Dressed in a blue sweater with a Union Jack motif, the tiny royal happily bounced on his mom’s knee as the varied procession of musicians, dancers, acrobats and carnival floats passed by the royal box outside Buckingham Palace.

Eugenie and Jack welcomed their first child in Feb. 2021. He is the ninth great-grandchild for the Queen and Prince Philip, and the first grandchild for Eugenie’s parents. Although Princess Eugenie has shared a number of photos of August on Instagram, she has been careful not to show his face.

Chris Jackson – WPA Pool/Getty Princess Eugenie and Jack Brooksbank

Eugenie’s sister, Princess Beatrice, and Beatrice’s husband, Edoardo Mapelli Mozzi, brought Mapelli Mozzi’s son from a previous relationship to enjoy the festivities. Christopher Woolf, known as “Wolfie,” stepped out for his first royal event. The couple left their daughter, 8-month-old Sienna Elizabeth, at home.

Beatrice and Edoardo’s July 2020 wedding (where Wolfie had the important role of pageboy!) marked the first time since Camilla, Duchess of Cornwall married Prince Charles in 2005 that a member of the British royal family stepped into the position of stepmother. Beatrice is the first of her generation — and first grandchild of the monarch — to do so.

“Beatrice is a wonderful and very hands-on stepmom,” a source previously told PEOPLE.

LONDON, ENGLAND - JUNE 05: Princess Beatrice of York, Princess Eugenie of York and Edoardo Mapelli Mozzi arrive to attend the Platinum Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Ben Stansall - WPA Pool/Getty Images) — LONDON, ENGLAND – JUNE 05: Princess Beatrice of York, Princess Eugenie of York and Edoardo Mapelli Mozzi arrive to attend the Platinum Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Ben Stansall – WPA Pool/Getty Images)

Ben Stansall – WPA Pool/Getty Princess Beatrice, Princess Eugenie, Wolfie and Edoardo Mapelli Mozzi

On Thursday, August enjoyed his first Trooping the Colour, watching the flypast by the Royal Air Force in the arms of Jack.

Prince George, 8, Princess Charlotte, 7, and Prince Louis, 4, also got into the carnival spirit on Sunday, with the parade led by the Gold State Carriage featuring a video image of the Queen waving to the crowds on her coronation day in 1953.

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LONDON, ENGLAND - JUNE 05: (L-R 2nd Row) Victoria Starmer, Keir Starmer, Lena Tindall, Zara Tindall, (front row) Prince Louis of Cambridge, Princess Charlotte of Cambridge, and Prince George of Cambridge watch the Platinum Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Chris Jackson - WPA Pool/Getty Images) — LONDON, ENGLAND – JUNE 05: (L-R 2nd Row) Victoria Starmer, Keir Starmer, Lena Tindall, Zara Tindall, (front row) Prince Louis of Cambridge, Princess Charlotte of Cambridge, and Prince George of Cambridge watch the Platinum Pageant on June 05, 2022 in London, England. The Platinum Jubilee of Elizabeth II is being celebrated from June 2 to June 5, 2022, in the UK and Commonwealth to mark the 70th anniversary of the accession of Queen Elizabeth II on 6 February 1952. (Photo by Chris Jackson – WPA Pool/Getty Images)

Chris Jackson – WPA Pool/Getty Prince Louis, Princess Charlotte and Prince George

Mia, 8, and Lena Tindall, 3 — the daughters of Zara Tindall, Princess Anne’s daughter — also enjoyed the spectacle of 10,000 performers celebrating on the streets of London drawn from across the U.K. and Commonwealth and comprised of volunteers, performers, key workers and figures from music, film, sports and the arts.