On Thursday 32-year-old Holly showed her support for the Virgin Strive Challenge in London.
Richard Branson's eldest child was joined by her brother Sam and his wife Isabella, whose sister is Prince Harry's ex-girlfriend Cressida Bonas.
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Left to right: Natalie Imbruglia, Princess Beatrice and Holly Branson
Adding a royal touch to proceedings was Princess Beatrice, who is a close friend of the Branson family and whose boyfriend Dave Clark works for Virgin Galactic.
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2013 Wimbledon champion Marion Bartoli, singer Natalie Imbruglia, comedian Jack Whitehall, winner of The Voice Jermain Jackman and Richard's photographer nephew Noah Devereaux also made up the party of famous faces supporting the Strive Challenge.
Stars including Jack Whitehall, Jermain Jackman and Marion Bartoli are part of the Strive team
Noah, Sam and Marion are part of the core team of ten people who will undertake the challenge, attempting to reach the summit of the Matterhorn in Switzerland from London.
Joined by stars and professional including Ben Ainslie and Ned Rocknroll, the group will run, row, cycle, hike and climb over 1,000km.
Richard Branson himself will be joining the adventurers, as will his sister Vanessa and her husband Robert Devereaux.
Great-grandmother-to-be, Eve Branson joined her grandchildren Holly and Sam
Holly was due to join the members of her family taking part in the challenge but had to pull out due to her pregnancy.
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"As one of Big Change's Trustees, some of you have been asking why I'm now not taking part in the Virgin STRIVE Challenge myself," she posted on her father's website. "Well, Freddie and I are delighted to share the happy news that we are expecting twins!"