The Audi S3 Cabriolet has been spied undergoing cold-weather testing in Europe, confirming that development of the German manufacturer’s first ever high-performance small-car-based soft-top is well advanced.

The revealing spy photos also serve as our first look at the basic design of the new-generation Audi A3 Cabriolet on which the sportier S3 variant will be based. Unlike the current hatch-derived A3 Cabriolet, the new convertible will share its underpinnings with the all-new Audi A3 sedan that is set to be unveiled later this year.

The result of the shift is a significantly sleeker profile for the new Cabriolet, doing away with the short and chubby styling of the current model for a look more closely resembling the larger A5 Cabriolet.

The more aggressively styled air intakes in the front bumper and the quad exhaust outlets of the spied prototype betray its camouflage as the sporty Audi S3 Cabriolet variant.

The likely flagship model in the new A3 Cabriolet line-up (unless Audi is working on an even more hardcore RS3 Cabriolet), the S3 convertible is set to inherit the 221kW/380Nm 2.0-litre turbocharged four-cylinder petrol engine from its hatched S3 counterparts. Six-speed manual and dual-clutch transmission options will be available, while Audi’s quattro all-wheel-drive system will be standard.

With its international unveiling still some way off, the new Audi A3 Cabriolet is not expected to reach Australian showrooms until 2014, with the sporty S3 variant likely to expand the line-up in the following months.

The third-generation Audi A3 hatch is set to launch locally around May 2013, with the S3 hatch joining the range in the second half of the year.