UPDATE: Revealing new images have been added to this article's gallery, including a first look at the new CLS's interior.
The next-generation Mercedes-Benz CLS has been spied during development testing in Germany this week.
Reports suggest that although the swooping new sedan is understood to share its running gear with the E-Class, it will retrain the CLS badge rather than switch to CLE. This is yet to be confirmed, however.
The vehicle in the images looks very much like a stretched version of the recently-revealed E-Class Coupe, with the new Mercedes-Benz corporate coupe rump visible through the disguise and sloping roofline.
The CLS is set apart from the E-Class most clearly by its narrow headlight design, along with almost Volkswagen-like tail lamps at the rear.
The cabin presents no surprises, with the new CLS taking its cues again from the E-Class. That means there's a broad two-tier dash design with a set of four centre-mounted circular vents standing out as the key styling piece.
In terms of motivation, the new CLS will likely borrow its engine range from the new E-Class sedan, which includes a range of turbocharged petrol and diesel engines in four-, six- and eight-cylinder configurations.
A high-performance AMG variant is also a strong possibility, with the 450kW/850Nm 4.0-litre twin-turbo V8 from the AMG E63 S the likely powerplant for a CLS63 S flagship.
Thanks to the shared underpinnings with the E-Class family, there is also a possibility a plug-in hybrid (PHEV) version of the CLS could be offered.
Timing of the new CLS is still unknown, with the company's product roadmap revealed last July neglecting to mention the four-door coupe in its 2017 launch plans - pointing to a 2018 debut.