An Aston Martin DB5 used to promote the James Bond film Thunderball has sold for $6.4m (£5.2m) at the world’s biggest classic car auction in California.

The car, which was once owned by the British JCB billionaire and Tory party donor Lord Bamford, exceeded its auction estimate and became the world’s most expensive DB5.

Barney Ruprecht, of the auctioneer RM Sotheby’s, said: “We are beyond thrilled … and proud to have set a new record for the most valuable DB5 sold at auction. Beyond this new auction record, the enormous amount of interest in the car and excitement surrounding it ahead of the auction solidifies its status as the ‘most famous car in the world’, along with the collector car hobby’s great respect for the Aston Martin brand.”

The car used to promote Thunderball includes 13 modifications including a Browning .30-calibre machine gun in each bumper. Photograph: Richard Drew/AP

The DB5 was one of the star lots at the Monterey Car Week, which is expected to generate sales in excess of $380m. More than 100 cars are expected to sell for more than $1m each.

Sean Connery, who drove a DB5 in two of the 007 films, said: “These DB5s are amazing. I remember the Furka Pass tyre shredding [in a car chase in Goldfinger], as well as the promotional events with these cars – they have become increasingly iconic since Goldfinger and Thunderball. In fact, I bought a very fine DB5 myself relatively recently.”

The car is not the one used in the filming, but it is an almost exact replica commissioned by film-maker Eon Productions and used at promotional events for Thunderball. It includes 13 modifications created for Bond, including a Browning .30-calibre machine gun in each bumper, tyre slashers mounted on its wheel hubs and a bulletproof rear screen that can be raised and lowered from behind the rear windscreen.

Later on Friday a rare road-legal silver McLaren F1 car is expected to sell for between $21m and $23m. If it sells for more than $22.5m, it will become the most expensive British car ever sold.

• This article was amended on 21 August 2019 because an earlier version referred to a 30-calibre machine gun, when .30-calibre was meant. This has been corrected.