Lamborghini's upcoming V12 hybrid supercar that will act as a successor to the Aventador will officially have a pure electric mode, and CarBuzz has found out what it will sound like.

It has been a week to forget for Lamborghini after the design of the new supercar - which we expect may be called the Lamborghini Revuelto - was leaked via patent filings in North Macedonia (that have now been removed). Now, another similar leak has occurred, as Lamborghini filed a sound byte with the European Union Intellectual Property Office (EUIPO).

Expecting the howl of a V12, we were surprised to hear a strange humming noise that sounded almost exactly like an EV's pedestrian warning noise, and that's because that's exactly what it is. Filed under categories 9 and 12 (which are for acoustic alarms, horns for signaling, and horns for a variety of vehicles, including electric cars and hybrid cars), this is the sound the hybrid Lamborghini will use when it's in pure electric mode.

The clip is broken into three basic soundbites, with the first demonstrating a steady throttle application. The second is most interesting as it sounds like a vehicle accelerating, but what's most interesting is that the volume fades as the 'revs' increase. The only reason for this to occur would be that as the acoustic warning signal fades, the V12 engine will come to life, creating a noise loud enough for pedestrians to hear.

The third element of the soundbite fades in from the higher speed and gets louder as its intensity diminishes, suggesting this will be used as the car slows and the V12 combustion engine switches off, transitioning to full electric mode once more.

Before now, details of the hybrid V12's powertrain have been scarce, with no knowledge of whether it would be a plug-in hybrid, traditional hybrid, or merely adopt the supercapacitor technology of the Sian. It was the latter that company CTO Rouven Mohr suggested will feature, but this new sound clip suggests otherwise.

Supercapacitors are great at charging and discharging bursts of energy rapidly but do not retain power for long enough to be able to sustain e-driving. Unless Lamborghini has developed the technology to the point that this is now viable, it would appear the hybrid Lambo will have a traditional hybrid battery pack of sorts. Whether it will be plug-in or not, however, is still a mystery.

We shouldn't have to wait too long, however, as a reveal is likely to happen in the next few months.