At the launch of the new 2021 Panamera last month, it took down the record as the fastest executive car at the Nürburgring – a distinction the AMG GT 63 S held for almost two years. Mercedes hit back at Porsche a few weeks later, teasing that the automaker will be going back to the 'Ring more likely to regain its crown.

It looks like the silent war at Stuttgart is moving forward as an AMG GT 73e has been spotted warming up Green Hell by YouTube's statesidesupercars. At this point, it's only a matter of time before Mercedes announces a new lap record together with the hybrid four-door coupe's debut – if at all.

Gallery: Mercedes-AMG GT 73 spy photos

Identified as a hybrid model through the yellow sticker, the GT 73e here is expected to produce around 800 bhp (597 kilowatts), pulling motivation from its 4.0-litre twin-turbo V8 and electric motor. Of note, that's a huge jump in output from the 630 bhp (470 kW) and 664 lb-ft (900 Nm) of the GT 63 S.

With these numbers laid out, Panamera's record-breaking run at the 'Ring could be short-lived, but that's yet to be made official by Mercedes. If it's any indication, the spy video above looks promising and we can't wait for the hybrid model's imminent debut.

Speaking of the debut, guess you could say that the AMG GT 73e (its alleged monicker) has been a long time coming since the first reports of the electrified model came out last year. We've already spotted its production-ready prototype several times, so it's more likely that a launch is right around the corner, probably toward the end of the year.

As always, we'll keep an eye out for any development, so watch this space.