Mercedes-Benz has hidden many of the car's styling features underneath a full-body camouflage, as well as false panels for the front and rear fascias, and a hump on the rear deck.
Despite these tricks, though, it's clear that the new four-door will look a lot like the AMG GT Concept sedan unveiled at this year's Geneva motor show.
Unlike the concept car, the production vehicle will have proper door handles and wing mirrors, as well as quad exhaust tips out the back.
Due to the stylistic similarity between the dour-door, and the GT coupe and convertible, it's possible the new model will keep the GT name, although we've heard the car referred to as the GT4.
A report earlier this year indicated the new sedan will not the use the exclusive underpinnings of the two-door GT models. Instead, the car will use the cheaper MRA platform, which underpins the mainstream Mercedes-Benz range, including the, C-, E- and S-Class.
Power, at least initially, is expected to come exclusively from AMG's 4.0-litre twin-turbo V8. To keep the new AMG sedan from tripping over the CLS' toes, the next-generation of the latter will reportedly not be offered with the option of a V8 engine.
AMG's twin-turbo V8 powered the GT Concept in concert with an electric motor. Together they were said to generate over 600kW of power, and drive all four wheels.
The production version of the Mercedes-AMG GT sedan is expected to make its debut in 2018.