We've already seen camouflaged prototypes of the BMW 8 Series preparing to battle the Porsche Panamera. This, however, is by far the most revealing look yet, as this prototype photographed sitting on a transport truck is mostly devoid of camouflage apart from a few layers applied to the rear fenders and trunk lid.

Unsurprisingly, the front fascia looks very similar to the 8 Series Coupe with its slim headlights and wide grille, while the profile retains its coupe sibling's sharp design lines. However, the body has been stretched from the A-pillar to create a flatter roofline and make room for two extra doors while creating more space in the back for rear passengers. The result is one seriously sleek-looking sedan. Judging from the bumper, we appear to be looking at the sportier M850i model.

As for engine options, the choice of powertrains will carry over from the 8 Series coupe. The M850i is powered by a 4.4-liter twin-turbo V8 that sends 523 horsepower and 553 lb-ft of torque through an eight-speed automatic gearbox. A range-topping M8 Gran Coupe is also coming, which will pack a twin-turbo V8 producing at least 600-hp and an advanced all-wheel-drive system that can be switched to pure rear-wheel-drive.

Inside, the 8 Series Gran Coupe will likely pack BMW's latest infotainment technology including a 12.3-inch digital instrument cluster paired with a 10.25-inch display and an extensive range of driver assists.

We don't have to wait too long for the covers to come off BMW's upcoming executive sedan, either. BMW recently confirmed the 8 Series Gran Coupe is currently in the final stages of development and that the reveal will take place in Munich between June 25th and 27th before launching worldwide this September. Judging from these latest spy shots, it should be well worth the wait.