Cadillac ATS-V prototype was caught testing.

Our spy photographers just snapped the first photos of a prototype 2015 Cadillac ATS-V coupe out testing, and it appears that the BMW M4 will face some stiff competition. This is also our best look at a coupe version of the ATS, which we've spotted before wearing much more camouflage.

The ATS-V coupe, powered by a 400+ horsepower twin-turbocharged V6, has a more aggressive front end than the regular ATS, with a much larger lower air intake and chin spoiler - maybe even a power bulge hidden under the camo. An odd-looking grille with vertical bars hides behind the camouflage, though our spy photographer says General Motors has been equipping prototypes with fake grilles lately. Through the camo we can also make out either a set of foglights or extra air intakes on either side of the front bumper.

The car looks to be slightly lower with wider fenders, which fit a wider wheel-and-tire setup, but the wheels are test units that we'd be surprised to find on the production model. Within the wheels we can make out large brake calipers with solid rotors.

The pair of double-barrel exhaust pipes emitted a "healthy" note, according to our photogs, though much of the rear end is heavily camouflaged. The disguise does seem to be hiding a trunk lid spoiler, however.

Click through the photo gallery above to see for yourself.