Cadillac has revealed a drop-top version of the Celestiq, its hand-built rival to the Rolls-Royce Spectre.

Named the Sollei – 'sun' and 'leisure' – the new concept harks back to the Eldorado from the 1950s. It has been built as a demonstration of the company's new personalisation capabilities as it looks to challenge premium and luxury brands as varied as Mercedes-Benz and Bentley with its new line-up of EVs.

Its bold yellow paint finish – Manila Cream – is taken from Cadillac’s catalogue of shades used between 1957 and 1958.

The seats are trimmed in a matching shade of nappa leather and contain a pink pigment that is said to create a sunrise-like effect when viewed in daylight. This cue is replicated on the finish of the door to the interior drinks tray.

The seat backs, meanwhile, are trimmed with unstained wood veneers that have been hand-cut and laid in a ‘sunburst’ pattern.

Cadillac said it has also designed the Sollei to appeal to “bird-watching connoisseurs” and has enclosed a set of 3D-printed bird-calling whistles in the interior with a special leather-bound journal for recording finds.

The firm’s design chief, Erin Crossley, said: “Sollei reimagines the discovery of travel, envisioning a personalised driving experience that connects one with the natural world around them.”

Cadillac has yet to confirm whether the Sollei will be produced but, given it is based on the Celestiq, it seems likely.

The company said the convertible “pushes the boundaries of future bespoke commissions”, suggesting a handful could be built, in similar fashion to the Rolls-Royce Droptail.

The unveiling of the Sollei comes shortly after Cadillac confirmed it will be reinvigorating its efforts in the British market with the Optiq and Lyriq, rivals for the Audi Q4 E-tron and BMW iX respectively.

It currently sells only the XT4 crossover in the UK – in very small quantities and in one trim level.