The CLS is one of the most significant models for Mercedes-Benz. It’s the first generation of this four-door coupé that helped the German carmaker out of years of styling stagnation and generated renewed customer interest in the brand. Now Stuttgart is hard at work putting final developmental touches to the third generation of the model.

The second generation, which came eight years after the original, couldn’t replicate the success of its predecessor. So it will be interesting to see what lessons Mercedes has learned from that and tried to resolve with this model.

This prototype, spotted cold-weather testing in Sweden, wears heavy camouflage, including a layer of cladding that makes it appear to have a ‘Bangle Butt’. Also this does its job of concealing the actual shape of the rear pretty well, so it’s anyone’s guess how it will look. Although it shares its platform with the new E-Class, the photos suggest it will get a longer wheelbase and a much more stylish silhouette.

Powertrain options should include a six-pot in the lower models and a twin-turbo V8 in the top-spec ones.