FRANKFURT MOTOR SHOW: Lamborghini Sian leaked

An image of what appears to be Lamborghini's electrified hypercar has been leaked ahead of its global debut at the Frankfurt motor show on September 10.

The image, posted on Instagram by Lamborghinisian, is claimed to have been posted on Lamborghini's Unica owners app.

Originally, it was thought the car revealed at Frankfurt might be an updated version of the wild pure-electric Terzo Millennio concept.

But the latest pic shows that aside from shared frontal styling and Y-shaped LED lamps, the car expected to be called the Lamborghini Sian will get an exterior design that owes more to the Centenario.

Look closer, and the Lambo hypercar features '63' numbers on the end plate of the rear spoiler, hinting at the ultra-limited production run of just 63 cars.

Developed under the codename 'LB48H', the Sian is rumoured to be powered by a 48-volt mild-hybrid version of the car-maker's current naturally-aspirated 6.5-litre V12.

Instead of batteries, the Lamborghini hypercar is understood to use the same supercapacitors that were previewed by the Terzo Millenio.

Rumoured to produce around 1000hp (746kW), the electrified V12 will be combined with a seven-speed dual-clutch transmission and all-wheel drive.

At Frankfurt, Lamborghini is expected to announce that all 63 cars are already sold, with each selling for around $2.5 million ($A3.7m).

The new standalone hypercar could enable Lamborghini to go racing against the Aston Martin Valkyrie in the new World Endurance Championship hypercar class, but all will be revealed next week at the Frankfurt show.

Despite the limited numbers, Lamborghini's new hypercar is expected to be hugely influential with its new hybrid powertrain and active aero both tipped to preview technologies employed in the next-generation Aventador due in 2024.