AUDI’S five-door TT variant has been one of the car world’s worst-kept secrets and at last Thursday’s Paris Motor Show opening the reveal of what is basically a pre-production concept car  confirmed what everyone knew – that it is now a matter of ‘‘when’’, not ‘‘if’’.

According to Audi’s head of technical development, Ulrich Hackenberg, the design is a fusion of the A5 Sportback and A7 Sportback designs and the result is an elegant car that is slighter longer than the TT coupe in length and wheelbase, giving rear seat legroom.

At 4470mm long, 1890mm wide, 1380mm high and with a 2630mm wheelbase Sportback is 290mm longer, 60mm wider and 120mm longer in the wheelbase than the new TT but 30mm lower overall.

Showing it means business, the show car ran a 294-kilowatt version of Audi’s 2.0-litre turbocharged engine, a seven-speed automatic and Quattro all-wheel-drive. The body and chassis use  lightweight aluminium components and, like the production TT coupes and roadsters, the Sportback runs Audi’s virtual cockpit with a 31cm screen replacing conventional instruments and the MMI monitor.

Audi is not putting any definite time line on a production version but it is probably fair to expect an announcement at next year’s Frankfurt Motor Show.