The CIEL, pronounced “C-L”, was named after the French word for “sky” and Cadillac says it is inspired by the California coast line and the brand’s classic styling cues. Designed by British-born Niki Smart, also responsible for the Ariel Atom, it has a the proportions of Cadillac’s old grand tourers but with a more environmentally conscious drivetrain.

Under the huge bonnet is a 3.6-litre twin turbocharged petrol engine, mated to a hybrid drive setup that allows it to operate on electric power when cruising at low speeds. Measuring over five metres long, it mixes the modern stacked headlights of Cadillac’s latest cars with the carmaker’s trademark classic rear fins.

Though unlikely to make it into production, it’s another step closer to partial electrification for Cadillac’s large luxury cars. On Wednesday General Motors announced that the Converj range-extended electic vehicle, which uses a similar powertrain to the Chevrolet Volt and Opel/Vauxhall Ampera, would be going into production as the ELR coupe.