Nope, as these spy photos confirm, there's a BMW 8 Series Gran Coupe. Per BMW naming tradition, "Gran" indicates four doors and "Coupe" therefore means nothing at all. It would replace the 6 Series Gran Coupe, and also theoretically serve alongside the M760i as a range-topping BMW four-door. (BMW also totally teased its existence months ago.)
Judging by the large air intakes up front and the parallelogram exhaust outlets, we're guessing this particular car is a BMW M850i xDrive Gran Coupe. What appears to be Estoril Blue paint, or some other vibrant M color, would be circumstantial evidence. One of the only differences we can spot is the Gran Coupe's small rear diffuser. Blowing up one of the profile images reveals a tiny glimpse of the interior, which appears to share the non-gran coupe's design. Note the screen rising from a center stack angled toward the driver. Again, not surprising.
One more important observation is the roofline. Compared to the 6 Series Gran Coupe, the 8's roof extends farther back and therefore remains higher over the rear passenger compartment. The back door window is also clearly bigger. This should mean a welcome increase in back seat headroom, which was always an issue in the four-door 6. In other words, it'll be even more like a sedan than a coupe, which in this particular way, is no bad thing.
Given how close-to-production this test vehicle looks, we're guessing we'll be seeing the camo pealed off for an official review very soon.