Now that the new Mercedes C-Class Sedan has debuted, it's only a matter of time before its next-generation GLC sibling breaks cover. We got our first look at the new GLC in prototype form last year, and now cold-weather testing for the redesigned luxury compact SUV has begun as it gets closer to production.

Since it launched in 2016, the current GLC has become the German automaker's best-selling SUV, so the importance of the all-new model cannot be understated, particularly as competition in the premium SUV segment has increased with new versions of the BMW X3 and Audi Q5.

Two prototypes were spied playing in the snow, and while they're both wrapped in camouflage, it's clear that the new GLC will be longer and wider than its predecessor, allowing for a more spacious cabin that could have room for up to seven seats. For reference, the current GLC is 183.3 inches long, 64.7 inches high, and 82.5 inches wide, with a 113.1-inch wheelbase.

Expect the new GLC to sport a new grille and slimmer headlights and taillights to give the compact SUV a more contemporary look. Like the C-Class Sedan, the new GLC will be underpinned by Mercedes' Modular Rear Architecture that will reduce the SUV's weight.

We don't get a look inside the interior, but it should have a lot in common with the C-Class Sedan's cabin, which has an 11.9-inch portrait screen with the latest MBUX infotainment system and a 12.3-inch digital gauge cluster. In terms of engine options, the new GLC will be offered with a range of electrified four-cylinder units.

Since the prototype is still fully camouflaged, we're expecting the next-generation Mercedes GLC to debut later this year or early next year and go on sale in 2022. It will also spawn a new stylish GLC Coupe, enabling Mercedes to compete with the BMW X4.