First previewed by the X7 iPerformance concept, BMW's answer to the Mercedes GLS and Range Rover is nearing production. And as you can see from these latest photos sent by our spy photographers, it's quite a behemoth. Set to become BMW's biggest SUV ever, these new spy shots give us a first look at a pre-production prototype X7 being loaded onto a truck on its way to a test facility. The X7 will be BMW's first full-size SUV with room for up to seven occupants in its spacious cabin.

The prototype shows the two rear seats are in an upright position, but when used as a five-seater it's safe to say the X7 will offer considerably more cargo space than the X5. There should be plenty of legroom for passengers using the second-row seats too, and getting in and out of the X7 looks hassle-free thanks to the long rear doors. Our spies also managed to snap some shots of the interior allowing us to have a peak inside BMW's lavish SUV before it enters production. Clearly, the cabin is still a work in progress. As you would expect, the X7 sports a fully digital instrument cluster but look closely and you can see it depicts the 7 Series, so the prototype is still running on the sedan's software.

Nevertheless, it still gives us an idea what the production X7 should look like inside. The X7 is based on a stretched version of BMW's CLAR platform, which also underpins the 7 Series, 5 Series and the new X5. Under the hood, expect the X7 to be offered with a range of six- and eight-cylinder engines in both gasoline and diesel guises, though we doubt the latter will be available in America. Nothing has been confirmed yet, but a plug-in version is also likely to happen. BMW's new Range Rover Rival is expected to debut later this year, possibly at the LA Auto Show in November.