Introduced in its current iteration about five years ago now, the Mercedes-Benz GLS-Class is starting to grow a little long in the proverbial tooth. Especially with so much fresh competition at the top level of the marketplace for luxury SUVs. Fortunately Daimler is working on a new one, and here we have it.

Spied undergoing winter testing is not just the “standard” version of Benz’s next-generation flagship crossover, but the AMG performance model. You can tell that much from the Panamericana grille, front-bumper intakes, wheels, and brakes – all larger than we’d expect on the lower-powered version.

Under the hood, we’re fully expecting AMG to slot its 4.0-liter twin-turbo V8. The engine produces 571 horsepower in standard guise, and 612 hp in S spec.

And a good thing, too, considering the competition the new GLS will have to contend with. The Bentley Bentayga has been muscling in on the big Benz’s territory, and soon there’ll be new challengers coming in the forms of the BMW X7 and Rolls-Royce Cullinan as well. All the while Land Rover keeps producing more luxurious versions of the Range Rover, with rivals like the Cadillac Escalade, Lincoln Navigator, Lexus LX, and Infiniti QX80 vie for slices of the big luxury sport-ute segment.

The 63 might not be the only AMG version, either, as we could see the mild-hybrid 53 and twelve-cylinder 65 engines slot in under the big hood as well. Of course there’ll be base Benz versions as well, but we’re also anticipating Mercedes to finally produce a Maybach version of the new GLS. That ought to help fend off the advances of the aforementioned Bentayga and Cullinan in an ever-escalating battle for the very pinnacle of the market.

Look for the new GLS to begin reaching dealers sometime next year.

Photos by CarPix