Take one of the most regrettable cars ever conceived, throw in a V8 and a host of mods, and voila! Suddenly cool. Well...

Remember the Aston Martin Cygnet? Platform sharing has created some strange tie-ups throughout history, but the Cygnet was one of the strangest, sharing its underpinnings with the lowly Toyota iQ. Perhaps unsurprisingly, it was an absolute flop.

You might be surprised, then, to hear the Cygnet is making a return in 2018. It's definitely not a Toyota anymore, with a 4.7-litre naturally-aspirated V8 engine, a race-ready interior, and some tough bolt-on arches. In other words, it's a proper Aston Martin this time around.

This isn't a production car, though. It's a one-off commission, created for a particular customer by the team in Aston Martin's bespoke 'Q', department, which managed to squeeze the outgoing Vantage S powertrain into what was (at one point) a Japanese city car.

The basic right-hand drive shell was treated to a roll-cage, a new front bulkhead and a fresh transmission tunnel, all of which were necessary to house that big V8. A 30L steel fuel tank sits in the boot, while the suspension and subframes are derived from those of the old Vantage.

Speaking of the engine, it produces 313kW of power and 490Nm of torque, put to the rear wheels through a seven-speed Sportshift II paddle-shift transmission. With all that grunt in a 1375kg package, the Cygnet will hit 60mph (97km/h) in just 4.2 seconds and runs to 170mph (274km/h) at full noise.

Given those outputs, the regular 16-inch wheels weren't really going to cut it. Aston Martin has fitted 19-inch rear wheels wrapped in 275/35 rubber down back and 235/40 tyres up front, with 330mm and 380mm brake discs on each respective axle.

The brake calipers are painted yellow to contrast with the green paintwork, naturally.

The interior is a curious mix of Cygnet and Vantage GT3, with Aston Martin suggesting the car could "easily be used for competition".

The compact city car's frame houses a beautifully-finished roll-cage, race bucket seats, a four-point harness and chunky carbon replacements for the stock dash and transmission tunnel – and there are no rear seats, so the kids will need to stay at home.

You still get a few creature comforts, in the form of a bespoke climate control system and two (count them!) USB ports on the centre console. The car's Vantage S connection is reinforced by the instrument binnacle and parts of the dashboard borrowed from the now-obsolete sports car.

“The V8 Cygnet shows the fun side of both Aston Martin and its customers," said David King, Aston Martin vice president and special operations officer.

"It is also a fine example of the engineering talent within the company as it’s no small achievement to fit the Vantage’s V8 engine so harmoniously into the compact body of our little city car. I am sure that it will amaze and thrill people when they see and hear it on the hill at the Festival of Speed.”

Given its status as an ultra-exclusive one-off, Aston Martin isn't quoting a price for the Cygnet V8. We're willing to wager it wasn't cheap... The car will tackle the Goodwood hillclimb this weekend, in what's sure to be one of the more interesting runs of the Festival of Speed.