Jaguar’s new XK supercar is a stunning looking car, bound to turn heads wherever goes. It has the beauty and sleekness of some of the old Jaguars of the 1960s. Yet like those masterpieces, the real story of the new XK, and what sets it apart from its competitors is what lurks beneath the paintwork.

No, this time it is not some sensational engine, as it was with the XK120, but the fact that the body is made from aluminum - like the new Jaguar XJ.

The idea of using aluminum – Honda started the trend 15 years ago with the NSX, and was quickly followed by Audi with the A8 – is to reduce weight. Honda reduced a lot of weight with the NSX sports car – the body was 40 per cent lighter than if had been made from steel.

Aluminum bodies last longer than steel ones because the metal does not corrode like steel, and they also absorb crash impact well – so they are safe. Now, several auto companies use aluminum for some body parts, but Jaguar is a world leader in making cars from aluminum sheet and extrusions.

There is no doubt that the new car is light. After all it is 300 lb lighter than the previous model, and is actually slightly larger. Not sure why the new car is bigger as the old one is a pretty big car. Here are the figures:

New Jaguar XK 3,513 lb (1,595 kg)

Current XK 3,820 lb (1,734 kg)

BMW 650i 3,778 lb (1,715 kg)

Mercedes-Benz SL500 4,064 lb (1,845 kg)

Compared with these competing supercars the new XK comes out very well. It is 250 lb lighter than the BMW and makes the Mercedes look the overweight fatty it is.

Yes, the new XK is a lightweight, but not in the way that the Lotus Europa S or Elise compete with their rivals. Sure, it is a good deal lighter than old fat 1990s design, but unfortunately Jaguar bosses wanted the car to have all the bells and whistles of a luxury sports car rather than the light weight of a super sports car. These all add weight. And they decided to make the car a bit bigger.

Even so, as a lightweight luxury sports car or supercar, the new Jag will do well. Why? Because it looks terrific - a real show stealer –has good performance thanks to that reduced weight, and handles like a much smaller car.

The engine guys have done a pretty good job of improving the response of the V-8 engine so that the 300 bhp mill gives much better performance than the current model. Once they put the supercharged engine in, the car will surely be a real cracker. And when you park it and look back, you’ll be sold on the Jaguar XK supercar every day of the year!

John Hartley is editor of fast-autos.com fast-autos.com, an online magazine devoted to fast cars and supercars. He has written from many of the world’s top auto magazines, and has written about 10 books about cars and the auto industry, including ‘Suspension and Steering Q&A’ and ‘The Electronics Revolution in the Motor Industry’. He has been writing about fast cars and testing them for over 20 years, and has been involved in race car design, and has also raced cars