Prince Andrew, 63, was dressed in riding gear and a helmet as he was joined by an aide for a trot around Windsor Great Park on Saturday, near his home, Royal Lodge.
Like his late mother Queen Elizabeth II, the Duke shares his family's love of equestrian sports.
And despite his divorce from Sarah, Duchess of York in 1996, the pair have remained on good terms and still live together at Royal Lodge.
Andrew and Sarah are grandparents to Princess Eugenie's sons, August, two, and six-month-old Ernest, and Princess Beatrice's daughter, Sienna Mapelli Mozzi.
The Duke has only made a handful of public appearances since stepping as a senior royal in November 2019, following his TV interview with BBC Newsnight, which focused on his connections to convicted sex offender Jeffrey Epstein.
In February 2022, Andrew reached an undisclosed out-of-court settlement with Virginia Giuffre, after she sued him claiming she was trafficked by Epstein to have sex with the royal when she was 17 and a minor under US law.
Andrew has vehemently denied the allegations.
Ahead of the US lawsuit, the late Queen Elizabeth II stripped Andrew of his honorary military roles and he stopped using the style 'His Royal Highness' in any official capacity.
While Andrew no longer carries out public duties or attends major royal events such as Trooping the Colour, he reportedly joined his siblings at the service for the Royal Victorian Order at St George's Chapel in Windsor in March.
The Duke was made a Knight Grand Cross of the Royal Victorian Order in 2011.
And he wore his Knight of the Garter robes at Charles's coronation in May, despite having no official role in the historic ceremony.
He sat in the third row inside Westminster Abbey, next to eldest daughter Princess Beatrice and her husband, Edoardo Mapelli Mozzi.
Andrew is expected to join the King and Queen at Sandringham for Christmas. Last year, he was seen walking alongside his younger brother, the Duke of Edinburgh, as the royals made their way to the service at St Mary Magdalene Church.
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