With the Mercedes-Benz GLB set for its debut later this year at the Frankfurt Motor Show, the top-of-the-range AMG 45 version has been spotted undergoing road tests courtesy of our spy photographers. Before this, the ‘junior’ AMG 35 version has been spotted running tests as well.

Here photographed while testing in Southern France, the Mercedes-AMG GLB 45 gains access to the most potent of the firm’s turbocharged petrol four-cylinder engines as it is based on the same platform as that of the current W177-generation A-Class, which will offer 422 hp in peak A 45 S guise.

It remains to be seen if the AMG GLB 45 will take the same two-pronged route as the A 45 in offering base and ‘S’ models, though further along the AMG family tree, the AMG-fettled GLC 63 also comes in S guise with the full 503 hp.

As for the GLB 45 itself, it adopts the key AMG 45 visual cues, including the Panamericana grille and deeper air intakes up front, with quad tailpipes and rear bumper diffuser at the back. All this adornment goes on top of a body that was previewed on a concept car in Shanghai earlier this year, with a boxier design said to be inspired by the iconic G-Class.

The GLB 45’s chassis will similarly be upgraded to corral the engine’s greater outputs, with stiffer, lower suspension likely to feature here along with uprated brakes. Inside, the basic interior architecture can be expected to remain, with the addition of some AMG-specific detailing, likely to be found on an AMG steering wheel, upholstery trim as well as revised instrumentation visuals.

GALLERY: Mercedes-AMG GLB 35 spyshots