Britain's Prince Andrew doesn't know if he has "the balls" to abseil down Europe's tallest building.
The 51-year-old royal will be part of a group of 40 people who will scale the east side of The Shard in London in a bid to raise £1 million for the Outward Bound Trust, and he admits the stunt is nerve-wracking.
Andrew - who is chairman of the trustees of the educational charity - said: "It is the same for me as everyone else. Have you got the guts, the balls, whatever you like to call it, to step over the edge at 1,000ft? And the answer is 'we'll see'."
Despite the terrifying nature of the fundraiser, Andrew insists his mother Queen Elizabeth isn't worried about him because she is so used to her children doing "mad things".
He told the Evening Standard newspaper: "This mother doesn't worry, based on the fact that all her children have done exclusively mad things over a number of years and so she is quite used to it."
Andrew also has the backing of his oldest brother Prince Charles, who thinks the scheme is a "fantastic idea".
On September 3, the prince will abseil from a gangway less than a metre wide and two metres long on the 87th floor which is 309.6m high.
He will cover a distance of 250 metres, which will take about an hour, and finish on the roof of London Bridge station, level with the 20th floor.
Donations can be made at: descentoftheshard.com/the-descendants.
