These first photos of the new cabrio come a few weeks after the 2018 6 Series coupe was photographed out on public roads. While we can see that the car's overall proportions won't be too different to today's vehicle, it's hard to discern it's key styling flourishes.
That's because the company has fitted this prototype with false body panels around the fenders, boot lid, and doors. The join lines of these additional panels hint at a boot lid design similar to the controversial first-generation model, although the reality will no doubt be something a little more populist.
This development vehicle is also fitted with temporary head- and tail-light units.
With its use of high-strength steel, aluminium, and, even, a dash of carbon-fibre, the new 6 Series should be around 100 kilograms lighter than today's cars.
Under the bonnet, expect to see a selection of engines similar to that of the new 5 Series, which uses turbocharged four-, six-, and eight-cylinder motors.
At present the petrol 5 Series range includes the 185kW/350Nm 530i with a 2.0-litre four-cylinder, 250kW/450Nm 540i with a 3.0-litre straight-six, and the 340kW/650Nm M550i xDrive with a 4.4-litre V8.
On the diesel side of the ledger, there's the 140kW/400Nm 520d trims with a 2.0-litre turbo four-pot, and the 195kW/620Nm 530d with a 3.0-litre inline-six.
The 530e's plug-in hybrid drivetrain, which a total of 185kW/420Nm at its disposal and a 45km EV driving range, might also be available in some markets.
A late 2017 debut is expected for the 6 Series range. If that proves to be so, the new two-door models won't go on sale in Australia until some time in 2018.