Hammond, 47, was injured while shooting the Amazon Prime show in a remote part of Mozambique, east Africa, but has reassured fans that he is fine – and joked that his injuries were not serious enough to land him a book deal.
Writing on social media site DriveTribe, he said: “It's true, I did fall off a motorbike whilst filming recently for The Grand Tour in Mozambique.
“I banged my head, yes, along with pretty much everything else apart from my left thumb, which remains un-bruised.
“Can't tell you more yet about the how and why of it; that's all for later in the year on the show. As for injuries; well put it this way, I don't think I can get a book out of it.”
It is not known when the incident happened but Hammond’s co-star Jeremy Clarkson tweeted about being in Mozambique in early March.
Clarkson recently told The Sun that Hammond was left “badly” hurt.
The accident comes 11 years after Hammond was involved in a high-speed smash while filming for Top Gear in 2006.
The presenter was in a coma for a fortnight following the 288mph accident but made a full recovery despite having life-threatening head injuries.
The Grand Tour returns to Amazon later this year.