Like the S6 saloon and S6 Avant, the Sportback is powered by a new V8 twin-turbo 414bhp 4.0-litre TFSI engine.
It means the car can go from 0-62mph in 4.9 seconds and on to a limited top speed of 155mph.
Its lightweight body and Audi's 'cylinder on demand' technology – where the car deactivates four of the engine's eight cylinders – help maintain fuel efficiency. The car averages 29.1mpg.
The S7 comes with a seven-speed S tronic gearbox, air suspension and four-wheel-drive.
The car goes on sale later this year, although prices have yet to be announced.
Audi S6 and S6 Avant uncovered
Audi S7 revealed
Audi S8 at Frankfurt motor show
Audi 'S' gallery