Mercedes-Benz A-Class sedan leaked

The first official image of the all-new Mercedes-Benz A-Class sedan has been leaked as part of a promotional billboard ahead of its 2018 Beijing motor show reveal tomorrow, revealing a mature new look that will put the Audi A3 sedan on notice.

The new Mercedes-Benz A-Class sedan's front-end design appears almost exactly the same as that of the upcoming A-Class hatch. But the svelte, elongated rear-end gives the car a more sophisticated, upmarket image.

At a glance the longer, booted A-Class looks uncannily like a baby version of the all-new Mercedes-Benz CLS, while also borrowing a few design cues from the Mercedes Concept A sedan launched at another Chinese motor show -- Shanghai 2017.

Pitched initially at the world's largest car market – China – which favours sedans over hatchbacks, the new A-Class sedan will be a global vehicle sold in most major markets to combat the unexpected success the Audi A3 sedan has experienced.

Based on the new MFA2 architecture that underpins most small front/all-wheel drive vehicles in the Benz garage, the four-door A-Class will come with a range of turbo-petrol and diesel engines.

The new Mercedes-AMG A 45 sedan will challenge the Audi RS 3 sedan and is tipped to exceed 300kW, ensuring its status as one of the fastest and most powerful compact luxury sedans on the market.

The entry-level engine is expected to be a 1.4-litre four-cylinder turbo-petrol engine worth 120kW/250Nm.

The A-Class sedan will not spell the end of the CLA-Class, whose swoopy design is expected to be even more flamboyant to provide more space between it and the more conservative A-Class.

The CLA Shooting Brake will also return as Mercedes-Benz updates the rest of its MFA2 vehicles, including the GLA. Expect an all-new GLB-Class off-roader to be added too.

All these new vehicles are likely to be updated with the latest A-Class's new technologies – including a fancy new interior fit-out and tech upgrades – by 2020.

Almost every aspect of the car can be controlled without touching a button, as voice-control taking over duties usually handled by dials and buttons. Touch-screen functionality will also be part of the new Mercedes-Benz User Experience (MBUX) system.

More boot space, more smartphone connectivity, more luxury and improved fuel economy will be the hallmarks of the new A-Class, which is expected to arrive in Australia from around August 2018.