Audi is set to steal the headlines at the Detroit motor show, after rumours of a 500bhp V12 diesel Audi R8 concept car surfaced.

A German magazine claimed a diesel-powered Audi R8 could be built, making it the world’s first diesel-engined supercar.

But an Audi spokesman would not confirm if a diesel R8 is in the pipeline.

If the rumours are true, the Audi R8’s powerplant is likely be the 6-litre twin-turbocharged V12 currently fitted in range-topping Audi Q7s.

As well as having more power than the 414bhp V8 petrol R8 on sale now, it would more than double the current model’s 317lb/ft pulling power with over 700lb/ft on offer.

And as a result of this epic diesel power we would expect the time taken to cover 0-60mph to plummet from the standard 4.6 seconds to just under four.

Audi is also expected to premiere a petrol Audi R8 V10 at the Detroit show with just over 500bhp, to suit customers with more hardcore tastes than the current V8 petrol provides.

A diesel R8 would undoubtedly be Audi’s ultimate homage to the incredibly successful Audi R10 TDi Le Mans racing car which has dominated the French 24 hour event and the American Le Mans racing series for the past two years.

If it goes into production the Audi R8 V12 TDi will have incredible environmental credentials compared to its petrol competition – it is expected it would be able to return over 25mpg and be Euro V emissions compliant, ensuring its future viability.