The new name is supposed to reflect the car's positioning among its sedan siblings - where the flagship model in the three-box line-up is the S-Class, so the range-topping SUV will be known as the GLS.
But there appears to be a lot more to this facelift than just an extra letter in its badge.
The facelifted model gains new, more rounded headlight assemblies and a new bonnet, a more upright grille with strong vertical design highlights, and a more streamlined front bumper.
The rear sees some tweaks, too, with a revised rear bumper to keep things similarly swoopy, and new inlays in the tail-lights. Sleek, low-profile exhaust tips round out the changes.
No images of the car's interior have been provided as yet, but our sources suggest the updated model will see the adoption of the brand's larger 8.0-inch tablet-style Comand media screen in place of the integrated screen of the current model. As such, the centre console will see a rework, too.
As for what powers the 2015 Mercedes-Benz GLS SUV, there should be a range of new engines including an updated diesel engine and a new turbocharged petrol V8s - similar to those that are to be fitted to the brand's new GLE Coupe.
Currently, the GL SUV is sold in Australia in three specification levels - the GL350 turbo diesel, GL500 petrol V8 and the flagship GL 63 AMG. Mercedes-Benz Australia has confirmed the new-look model will arrive locally in 2016.
Read more about the new Mercedes-Benz model naming structure here.
Click the Photos tab above to see more images of the 2015 Mercedes-Benz GLS.