TV presenter Richard Hammond was rushed to hospital by helicopter after being involved in a car crash in the Swiss mountains.
The former Top Gear star, 47, is believed to have been filming a race scene for the second season of Amazon Prime series The Grand Tour.
Also on location were co-stars Jeremy Clarkson, 57, and James May, 54, who were unharmed, with Clarkson writing on Twitter afterwards; "It was the biggest crash I've ever seen and the most frightening but incredibly, and thankfully, Richard seems to be mostly OK."
Pictures of the crash soon began to appear on social media showing a large fireball engulfing the vehicle.
Police spokesperson Gian Andrea Rezzoli, from the St Gallen police, said the injured driver was rushed to hospital by air ambulance, the Swiss newspaper 20 Minuten reported.
They confirmed that he was conscious at the time.
He was pictured smiling alongside one fan just a few hours before with the location tagged as the Bergrennen Hemberg race.
It is thought to have been taken not long before the accident occurred, alongside the jokey caption: "New colleague".
According to BBC News, he "walked out of the car himself" and "has sustained a fracture to his knee".
An Amazon spokeswoman told The Sun: "Richard Hammond was involved in a serious crash after completing the Hemburg Hill Climb in Switzerland in a Rimac Concept One, an electric super car built in Croatia, during filming for The Grand Tour Season 2 on Amazon Prime, but very fortunately suffered no serious injury.
"Richard was conscious and talking, and climbed out of the car himself before the vehicle burst into flames.
"He was flown by Air Ambulance to hospital in St Gallen to be checked over revealing a fracture to his knee.
"Nobody else was in the car or involved in the accident, and we'd like to thank the paramedics on site for their swift response. The cause of the crash is unknown and is being investigated."
Hammond was previously involved in another horror collision in 2006 while filming for Top Gear.
During the incident, his helmet embedded itself into the ground with the visor open, forcing soil into his mouth and damaging his left eye.
Hammond had been attempting to break the British land speed record.
Although lucky to escape with his life, the dad-of-two, who has been married to Amanda Etheridge for 15 years, suffered brain injuries and later reported loss of memory, depression, plus, difficulties with emotional experiences.
"For years I thought of it especially," he said in an interview with Radio Times.
"It was a lot to deal with. I had a pretty tricky few years. The knock-on effects of the injury meant I was susceptible to depression, obsession, compulsion and paranoia, although I wasn't aware of that at the time. It gave me an unnatural platform from which to observe my own mental state, which was exhausting."