The third-generation Audi TT has been spotted for the first time, testing on public roads in Germany and at the Nurburgring.

The model was seen performance testing against rivals including the Peugeot RCZ, BMW Z4 and Mercedes SLK.

Based on VW's MQB platform, which allows for a shorter front overhang and longer wheelbase, the next-generation TT will be launched with both front and four-wheel-drive variants.

Engines are likely to include the latest slimmed-down 1.8-litre and 2.0-litre EA888 petrol engines, which will include fuel-saving Cylinder on Demand technology. A mildly updated direct-injection 2.0-litre diesel will also be in the line-up. In 2015, a reworked version of the 2.5-litre five-cylinder engine will make its debut in a new high-performance TT RS.  

A new six-corner grille, more angular headlights and a contoured clamshell bonnet can all be seen here, as well as the TT's standard rounded tail and motorised tail spoiler. The wheel arches of this test mule also appear to be more sculpted in appearence.

Previously, Audi told Autocar it wanted to mix elements of both the current TT and the original model into the new car. The company said the aim of the new TT would be to recapture some of the distinctiveness and impact of the first-generation model.

The new Audi TT is likely to launch towards the end of 2014 as an MY2015 car.