The royal, 35, joined her husband Edoardo Mapelli Mozzi for the event - which commemorated the best-selling '2 Weeks to A Younger You' - at the Broadwick Soho Hotel.
Despite the royals being famous for enjoying sporty pursuits and the London Marathon ending right by Buckingham Palace, only one member of the Windsor clan has actually done it.
CRAIG BROWN: Princess Beatrice 's husband, Edoardo Mapelli Mozzi , describes himself as the 'Founder and Creative Director' of a company called Banda.
In the first throwback image, the stepson of Princess Beatrice, 35, sat in a sling wrapped around his mother as a newborn on a beach in Lamu, Kenya.
Dara Huang, 41, who was in a relationship with Edoardo Mapelli Mozzi between 2015 and 2018, shares seven-year-old Wolfie with her ex, who is now married to Princess Beatrice.
The weather couldn't dampen spirits as revellers screamed and cheered on their horses while sipping on Champagne and dressing to impress.
Grey skies above Cheltenham didn't deter those attending the meet's final day, with broad smiles and an array of glamorous outfits coming through the turnstiles for day four of the British race meet.
Grey skies above Cheltenham didn't deter those attending the meet's final day, with broad smiles and an array of glamorous outfits coming through the turnstiles for day four of the British race meet.
Guests at Cheltenham in Gloucestershire were spotted brightening up the dreary day in check coats, vibrant hats and colour coordinated ensembles as they kicked off St Patrick's Thursday.
Guests at Cheltenham in Gloucestershire were spotted brightening up the dreary day in check coats, vibrant hats and colour coordinated ensembles as they kicked off St Patrick's Thursday.
William pulled out of attending the service for the late King Constantine of Greece for unspecified 'personal reasons'.
William pulled out of attending the service for the late King Constantine of Greece for unspecified 'personal reasons'.
Queen Camilla was instead the most senior member of the Royal Family in attendance - with Prince Andrew also enjoying a prominent role.
Thomas Kingston (pictured with wife Lady Gabriella Windsor), 45, was found dead at an address in Gloucestershire on Sunday evening and that emergency services were called shortly after 6pm.
The Royal Family turned out in force for the service of thanksgiving at Windsor Castle for the late King Constantine of Greece on Tuesday. Here, FEMAIL takes a closer look at the guests who attended...
The Duke of Sussex flew more than 5,000 miles from his home in California to London for what ended up being a 45-minute meeting with his cancer-stricken father King Charles.
Charles and Queen Camilla were seen waving to crowds as they left the royal residence in London in the back of an official car.
In a statement, the 65-year-old Monegasque royal sent his 'warmest thoughts and prayers' to Charles, 75, who is said to be 'on good form' following treatment earlier today for an unspecified cancer.
Charles and Queen Camilla were seen waving to crowds as they left the royal residence in London in the back of an official car.
Charles and Queen Camilla were seen waving to crowds as they left the royal residence in London in the back of an official car.
Charles and Queen Camilla were seen waving to crowds as they left the royal residence in London in the back of an official car.
