Despite numerous reports earlier this year that the 6 Series would be turned into a Porsche 911 fighter - with its sport-luxe GT spot taken by the anticipated 8 Series - it appears the new 6 Series will continue on the same path as the current model.
Photographers report that this development vehicle looks slightly smaller than the car on sale today - not larger, as an 8 Series would likely be, but also not small and lithe enough to be any sort of genuine 911 rival.
Up front there are sharper headlights and a wider grille, making the 6 Series appear wider and flatter than the current model - potentially bringing it in line with the recently-revealed 'G30' 5 Series and larger 7 Series.
Out back, pre-production tail-lights are being used, but the chunky rump stays true to the current car, while large trapezoidal tailpipes protrude from the bumper.
Under the bonnet, expect the new 6 Series to feature a similar engine line-up to the closely-related 5 Series range, including the range-topping 4.4-litre turbocharged V8 from the M550i xDrive, which in the sedan produces 340kW and 650Nm and shoots from 0-100km/h in just four seconds flat.
An all-out M6 variant will almost certainly join the range at some point, as well.
Like the current car, a convertible version is likely to follow, though a four-door GranCoupe body may not be on the cards.
It’s expected the 6 Series will sit below the larger 8 Series when it is launched towards the end of the decade - which is believed to be BMW’s direct competitor for the S-Class Coupe and upcoming Audi A9.
Timing of the new 6 Series is yet to be revealed, though it’s likely we’ll see more developments over the coming year.
Stay tuned to CarAdvice for more updates.
Click the photos tab for more images of the 2018 BMW 6 Series