BMW's has revealed this Concept 4-series Coupe, which finally confirms on one of the car industry's worst-kept secrets: that the two-door 3-series will be become the 4-series and join the 6-series as a two-door variant of a BMW sedan.

“The ‘4' doesn't just mark the start of a new cycle; it marks the start of a model with its own individual character and a stand-alone design,” says BMW.

The 4-series Concept Coupe will officially debut at the Detroit auto show in January, with the production car set tto appear shortly thereafter, Although billed as a design study, the 4-series concept is understood to be a faithful representation of the production car. It will be officially debuted Only some of the more extreme elements, such as the flamboyant front and rear bumpers and air dams, will be toned down, Autocar reports.

These first official pictures show the new two-door to be a muscular and broad-shouldered design draped over a wide-stance platform. BMW has released the key dimensions for the concept, which are expected to be carried over to the production car with very little change. The 4-series concept features a wheelbase that is two inches longer than the "3," is 1.7 inches wider and is just over half an inch lower in overall height.

Engine choices were not revealed, but the 3-series sedan's 2.0-liter turbocharged inline-four cylinder and 3.0-liter turbo six are expected to be retained.