Sir Richard Branson says he is "determined" to complete a 2,000km (1,250 mile) cycle, hike and swim just a dozen days after a near-deadly bike crash.
The 66-year-old said he was "very, very lucky" to escape the accident with cuts, a cracked cheek and a damaged knee, but was confident that he would complete the 30-day charity challenge from the base of the Matterhorn in Zermatt, Switzerland, to Mount Etna in Sicily.
In his first interview since the crash, he told the Press Association: "I was extraordinarily lucky, as anybody who goes through a nasty crash and survives is extraordinarily lucky, and I'm mending really rapidly.
"If you get knocked off your bike you've got to pick yourself up again and get back on again and these kids set the family a challenge every year and they have roped their father in."
Sir Richard, who was training for the Virgin Strive Challenge when the accident happened in the Caribbean on August 22, will be accompanied by his children Holly and Sam on the adventure, which begins on Friday.
The tycoon said: "Holly and Sam were actually there at the time and they definitely didn't think I'd be standing here on Strive a few weeks later.
"My knee is slightly damaged - I'm just going to have to see tomorrow whether I can make it up the mountain but I'm determined to give it my best shot."
Holly added: "He's literally the bionic man - he should have broken lots of bones but that didn't happen."
Despite the crash, Sir Richard said he had not been put off adventure sports.
"I've been through a few near misses in my life and I think what I've learned from it is that I love adventure and my kids have got the bug.
"I'd much rather come to grief doing something extraordinary and having an extraordinary life than sitting and vegetating watching television. I don't want to come to grief at all, but if I had to," he explained.
Along with a group of around 60 people, the team hopes to raise £1.5 million for Big Change - a foundation set up by Holly and Sam - to give young people the "necessary tools they need to thrive in life".
Big Change acts as a catalyst for a number of projects - including How to Thrive and Voice 21 - to accelerate their success.
The first group set off on Friday morning and a second will leave on Saturday.
They are starting the challenge from the base of the Matterhorn where the 2014 Strive Challenge, which started in England, finished.
Sam reached the summit of the Matterhorn on the last challenge, but had to be rescued by helicopter.
His cousin Noah Devereux, who came up with the idea for the Strive Challenge with Sam, said: "It was a real strive. Sam had to get rescued by helicopter from the summit because he was struck by acute mountain sickness and it was quite a serious situation for a bit, but luckily he survived to tell the tale."
Sam added: "After a year of planning and a massive event and a month's challenge, me and Noah waited for that moment - our dream come true on top of the Matterhorn - and Noah comes in to give me a hug and I throw up on his feet and burst into tears.
"It was not the ending I was expecting but it was magnificent."