Princess Beatrice was on hand to help to launch the Virgin STRIVE Challenge on Wednesday.
At the O2 Arena in London, the Princess was joined by celebrities including Brian Cox, Jack Whitehall and The Voice winner Jermain Jackman, to promote the ultra-endurance fundraising challenge organised by Sam Branson.
Several of the team scaled the O2 arena, wearing harnesses and ropes.
The challenge takes place between 7 August and 6 September, and involves a core team of people travelling from London to the summit of the Matterhorn in Switzerland.
Helped along the way by volunteers including Princess Beatrice, Ed Sheeran and Jamie Oliver, the team will run, cycle, row, and hike their way to the summit in Switzerland.
Jack Whitehall scales the O2 Arena
The team will be undertaking the challenge to raise money for Big Change, a charity which Princess Beatrice was involved in setting up, and which will help to improve the lives young people across the UK through developing life skills.
Speaking at the O2, Sam said: "I am incredibly excited to have created such a challenging event that will hopefully have such a positive impact on young people across the UK."
He added: "It has been so rewarding seeing it evolve from an idea with my cousin into a massive and very real physical event that will cross three countries, five different sporting disciplines and contain over three hundred and fifty participants."
The Virgin STRIVE Challenge team
Princess Beatrice recently began a work placement at Sony Entertainment in London, and last Friday the Princess spoke to pupils of Bolingbroke Academy and the ARK Globe Academy about her dyslexia.
"Dyslexia is not a pigeonhole to say you can’t do anything. It is an opportunity and a possibility to learn differently. You have magical brains, they just process differently. Don’t feel like you should be held back by it," she told the youngsters.
Both schools are supported by the Drive for Literacy programme, a partnership between ARK Schools and the Driver Youth Trust, to develop reading and writing skills.