Having been on sale in the US since 2015, the Audi A3 is due an update, particularly as the compact sedan is facing stiff competition from the new Mercedes-Benz A-Class. Spy shots have already confirmed that Audi is working on an all-new A3, but our spies have now spotted two partially uncovered prototypes.

There's no camouflage covering the front and side on one model, but the rest of the car is hidden under a sheet. The sedan looks virtually identical to the current model, so expect the styling changes to be subtle when the production version arrives.

The most notable difference is the wider grille and reshaped air intakes that bring the new A3 in line with other recent Audi models such as the new A4. Elsewhere, the headlights are missing, and the higher ride height suggests we could be looking at an empty shell with no engine or gearbox.

According to Audi, the new A3 will be better than its predecessor in every way thanks to improved ride quality and a revamped interior with more premium materials and tech normally reserved for more expensive luxury models. The new A3 will ride on an updated version of Volkswagen's MQB architecture, which supports hybrid and plug-in hybrid drivetrains.

This wasn't the only A3 prototype being tested, however, as our spies also caught the new Audi S3 playing in the snow, which will rival the Mercedes-AMG A35. Unlike the other two prototypes, however, the S3 is still fully camouflaged. While the current S3 produces 292 hp from a 2.0-liter turbocharged four-cylinder, the new model is expected to increase the output to around 300-320 hp.

The new Audi A3 is expected to debut at the 2020 Geneva Motor Show as a hatchback, which will be followed by a sedan variant in the US. Later in the model's lifecycle, Audi will also introduce the new range-topping RS3.