Aston Martin has produced some enduring classics over the years, but few can hold a candle to the DB4. The precursor of the DB5, DB6, and DBS that followed, the DB4 endures as the quintessential classic Aston, and with little over 1,200 of them built between 1958 and 1963, they remain highly sought-after. But this could be the rarest of them all.

Only around seventy DB4s were built as convertibles, and just 75 as DB4 GT coupes. This, however, was the only one known to have combined the two: a DB4 Convertible with the engine from the DB4 GT.

Chassis number 1173 is said to have been made for a close personal friend of David Brown, the company's owner and chief executive who lent his initials to Aston's line of grand tourers.

Now over half a century later, the Aston Martin Works heritage division is undertaking the unique vehicle's complete and comprehensive restoration, and will display it as a work-in-progress at the Retromobile show set to open next week at the Porte de Versailles in Paris. What's more is that it'll be up for sale, and we're left with little doubt that it'll find a new buyer.

"The decision to take chassis 1173 to Paris wasn't simple, but we wanted to give the enthusiastic and knowledgable Retromobile audience the chance to see this exceptional piece of Aston Martin history up close as it progresses through its journey towards concours condition," said Aston Martin Works heritage director Julian Wren. "Like our other cars at this exciting event 1173 is available to purchase, and I'm looking forward to discussing the car with enthusiasts and collectors alike."

Alongside the DB4 GT convertible, Aston will also display a 1960 DB4 Series II, a '68 DB6 Vantage, a manual-converted V12 Vanquish, and a rare Vantage V600 Le Mans edition.