May was at the wheel during a dangerous drag-style race in Norway for their hit Prime Video when the accident happened.
He was rushed to hospital for tests, including a brain scan.
Luckily, he was only left with a broken rib.
Speaking of the incident, which is believed to have happened a few months ago, for the first time, co-star Clarkson said: "It was a massive accident.
"You know when Hammond [who was involved in a devastating 2006 crash that left him in a two-week coma] has an accident, he keeps going after the accident has begun.
"And this is what people need to remember with accidents - you can roll down a road upside down and on fire for as long as you like, and it’s very unlikely you’ll get hurt.
"What hurts you is coming to a sudden stop. And that’s what happened to James.
Thank you for all your kind comments and funny jokes re my crash, but it was a while back, not that bad, and I’m perfectly OK.
Apologies to Evo fans for binning the VIII.#Bellend
— James May (@MrJamesMay) August 13, 2022
"Richard, when he went upside down, didn’t come to a sudden stop. That’s why he’s still here today."
The TV star, who will be back on screens on The Grand Tour presents: A Scandi Flick, when it launches on Prime Videoâ¯on September 16, continued: "I was standing right next to him when he crashed. I mean, 10 feet away. And I couldn’t believe how fast he was going."
Speaking on Thursday, Hammond also spoke about the crash, joking that May was trying to copy him by crashing.
"He's taken the only thing I had left, which was crashing," he told The Sun.
"It's very flattering that he would consider that level of impersonation, but I'll let him have that... He can have the crashing!"
Speaking of his recovery, he added: "It was a hell of an impact. It's pretty dramatic.
And I was surprised that all his limbs didn't just fall off."
Shortly after news of May's crash leaked last month, the former Top Gear host took to his Twitter to acknowledge the reports.
He wrote: “Thank you for all your kind comments and funny jokes re my crash, but it was a while back, not that bad, and I’m perfectly OK..."