SPY PICS: BMW X7 breaks cover

BMW has offered the option a third row of seats in its popular X5 for some time, but the Bavarian car-maker will soon produce its first fully-fledged seven-seat SUV in the shape of the X7, which has been confirmed for production and is due on sale in 2018.

As you can see from these first images of a heavily disguised X7 undergoing testing in prototype form somewhere in Germany, BMW's new SUV flagship will be bigger and more commodious than the X5.

That said, the spy photos indicate the X7 won’t be ridiculously bulky, suiting a role as a reasonably handy kindergarten/primary school shuttle rather than a no-holds-barred 4WD. In fact it’s being said the X7 will be available as an xDrive AWD, and in rear-drive form.

The all-new, full-size German luxury SUV will also sit above the X5 in terms of road presence, technology, equipment and price, which could be as high as $150,000.

No technical details have been officially revealed, but it's understood the X7 will be based on a longer-wheelbase version of the redesigned X5, which itself is expected to be fast-tracked into production next year.

Thus both US-built SUVs are expected to ride on BMW's latest 'CLAR' platform that underpins the new 7 Series limousine, which should also donate its advanced autonomous, safety and multimedia technologies.

Naturally the X7 (and new X5) is also likely to share the top-shelf BMW sedan's range of petrol and diesel four, six and eight-cylinder engines, as well as a plug-in hybrid powertrain – and perhaps even a version of the 7 Series' 6.0-litre V12 for a possible X7 M to rival the Mercedes-AMG GLS 63.

To help keep weight down to around 1900kg for the heaviest model, the seven-seat X7 will come with not only an aluminium-intensive structure, but with some body panels and parts made entirely of carbon-fibre.

Expect power-folding third-row seats, an eight-speed automatic transmission and air suspension to be standard on the X7, which looks set to become the biggest, most luxurious and expensive BMW production model ever created, apart from the M1 supercar.