2013 BMW 6 Series Gran Coupe spy shots

From the front you can easily spot the new 6 Series resemblance, with its pronounced upper grille section and newly-designed BMW 'Angel Eye' headlights. The lower grille also spreads across the entire width of the front end, just like the new 6 Series.

Looking at the side is where things start to differ from the normal Coupe model. BMW has squeezed in rear doors to provide a four-door coupe layout. This will be BMW's answer to the Mercedes-Benz CLS four-door coupe, and the Audi A7 Sportback.

Sharing the same theme as the Gran Coupe Concept unveiled at the Beijing Auto Show last year, the Gran Coupe name is also likely to be carried over to this production version. This will differentiate it from BMW's usual 'GT' name attached to sedan-based coupes, such as the BMW 5 Series GT and the predicted upcoming BMW 3 Series GT.

The back of the car showcases a more steeply raked rear windscreen compared with the normal two-door coupe. It is also likely to feature some changes in rear end detailing to help distinguish it from the other models.

Providing power for the new model is said to be same engine line-up as the BMW 6 Series Coupe and Convertible. This includes the 4.4-litre twin-turbo V8, producing 300kW, and the 3.0-litre turbocharged six-cylinder petrol engine, producing around 235kW. A diesel version might also be on the cards further down the track.

The BMW 6 Series Gran Coupe is expected to go on sale sometime towards the end of next year.