The all-new BMW 4 Series Convertible has been spied in its most revealing guise yet, giving us an almost unhindered look at the car's exterior design.

bmw-4-series-convertible-1

CarAdvice's spy photographers captured the production-specification test vehicle outside BMW's workshop at the Nurburgring in Germany.

bmw-4-series-convertible-3

The spied BMW 4 Series Convertible wears the new M Sport package, which is distinguished by the aggressive lines and black details of its front bumper, twin-arm five-spoke alloy wheels and large rear diffuser, as well as the interior’s red leather upholstery that can be seen through the windows.

The images also display clearly the lines of the Convertible’s folding hardtop roof, which splits into three pieces at the top of the windscreen, through the centre of the roof and above the rear window.

bmw-4-series-convertible-5

Like the outgoing 3 Series Convertible, the new 4 Series Convertible will closely mirror the styling and specifications of its 4 Series Coupe counterpart, which was unveiled earlier this month.

The BMW 4 Series Convertible is likely to launch with the same three engine and trim levels as the Coupe: the 135kW/380Nm 2.0-litre four-cylinder turbo-diesel 420d, the 180kW/350Nm 2.0-litre four-cylinder turbo petrol 428i, and the 225kW/400Nm 3.0-litre six-cylinder turbo petrol 435i.

bmw-4-series-convertible-7

Production of the BMW 4 Series Convertible is set to begin later this year before the new model goes on sale alongside the Coupe in early 2014.