Mercedes-AMG is hard at work dealing with the final niggles on its One hypercar, a process that might not see the car in customer hands until 2021.

Like us, you're probably dying to know what the car and its Formula One engine will sound like, and now we have a good indication thanks to a video of a prototype posted online by Instagram user zalasin.

No surprise that the car sounds like a real F1 racer. Why? For those who've been stuck under a rock, the AMG One uses the exact same engine found in the current crop of F1 cars raced by Mercedes-AMG. That would be a 1.6-liter turbocharged V-6 with an 11,000-rpm redline and an electric motor-geneator mounted to spin the turbo instantly.

Together with an electric motor-generator at the rear and another two motor-generators at the front, we'll see more than 1,000 horsepower from the One's powertrain. These are good times indeed.

Mercedes-AMG One

Mercedes-AMG One

All of the performance comes together to make some pretty spectacular specs. Top speed should be around 217 mph; 0-60 will happen in well under 3.0 seconds; and 0-124 mph will rocket by in under 6.0 seconds.

As is well documented, the car was originally due this year to take on Aston Martin's Valkyrie which is confirmed to start deliveries in the fourth quarter of the year. AMG has conceded that it underestimated the difficulty of getting the One's F1 engine to behave like a road car's engine (i.e. meet emissions standards and be stable at idle speeds), though the company is confident the car will be delivered with its promised specs.