Edoardo Mapelli Mozzi shared images of a fireworks display on Thursday evening, posting two clips to his Instagram story, which appeared to show a celebration taking place on a large country estate.
The 41-year-old property developer did not provide a location, and there has been no confirmation as to who was present at the event.
It is not known whether Princess Beatrice or the couple’s daughters, Sienna, four, or nine-month-old Athena attended.
Beatrice has only just returned to the UK following overseas work commitments. The princess spent part of last week in the Middle East, where she took part in panel discussions in both Dubai and Riyadh.
Her stepson Wolfie, nine, had been in Florida for half-term with his mother, architect Dara Huang, but is understood to have since returned to the UK.
The photographs posted by Mr Mapelli Mozzi showed bright trails of sparks rising into the night sky, followed by a high-burst firework illuminating the surrounding trees.
In both images, the figures lighting the fireworks could be seen only faintly in silhouette across the lawn.
The posts came on the same day Princess Beatrice and Princess Eugenie were seen sharing a long embrace in Mayfair during what appeared to be an emotional moment between the two sisters.
Princess Beatrice’s husband attends fireworks celebration after her return to UK
|GETTY / INSTAGRAM: EDO MAPELLI MOZZI
Their meeting marked their first public appearance together since significant developments concerning their father, Andrew Mountbatten Windsor.
Earlier on Thursday, Andrew was formally stripped of his princely title and HRH style after King Charles issued a Letters Patent, which was published by the Crown Office, the UK’s official public record.
The change means Andrew is no longer styled as a prince and will instead be known publicly by his family name.
The document was issued on the same day Andrew was instructed to appear before a Congressional committee in the United States to answer questions regarding his association with Jeffrey Epstein.
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Edoardo Mapelli Mozzi shared images of a fireworks display
|INSTAGRAM: EDO MAPELLI MOZZI
The move marked the most direct form of parliamentary scrutiny the 65-year-old has faced to date.
Beatrice and Eugenie, who retain their HRH styles, were photographed speaking intently as they walked together through central London.
Onlookers described the sisters as appearing sombre, with Beatrice in particular looking downcast as they parted ways.
Their embrace took place close to Green Park and a short walk from Buckingham Palace, underscoring the timing of what had unfolded within the royal household.
Princess Beatrice speaking on stage in Abu Dhabi | UAE-UK BUSINESS COUNCILRoyal sources have suggested the King wishes to ensure the sisters continue to carry out public engagements and charitable work without being overshadowed by their father’s situation.
Mr Mapelli Mozzi regularly posts images of countryside settings and has previously shared glimpses of family gatherings without providing details.
Beatrice, who balances royal duties with a role in the private sector, has maintained a largely low-key public profile in recent months.
Her return to the UK comes at a time of considerable personal and familial adjustment, though those close to her say she remains focused on her charity and advocacy work.