Hang on, let me check my lottery ticket before reading what follows.

That's probably a good idea. Is it a Rolls-over jackpot?

Very droll. I suspect it will need to be.

Oh yes, this one's not cheap. It's the Rolls-Royce Dawn - a new four-seat convertible from the great luxury car maker, which is kind of based on the Wraith coupé, but which Rolls says has a body that's actually 80 per cent all new compared to the coupé.

Oh, and it's a proper four-seater too. Rolls-Royce was very keen to point out that it has actual room for four actual people, unlike some other, more compromised convertible designs. The high fabric roof, 'French seamed' for extra smoothness, motors up and down in just 22 seconds in what Rolls-Royce calls the 'Silent Ballet.' It should be pretty silent at all other times too, as this is claimed to be the quietest convertible car in the world when the roof is up. Helpfully, and to avoid red faces at traffic lights, that roof can be moved at speeds of up to 30mph.

Power comes from the 6.6-litre turbo V12 engine from the Wraith and Ghost, and it still has 563hp and 780Nm of torque. The throttle response has been sharpened up though, by 30 per cent, while the suspension has been redesigned to cope with the car's extra weight and its shorter overall length.

Inside, aside from the four individual bucket seats, there are the usual lashings and lashings of leather and wood, and a new clock with the Dawn name inscribed upon it. There's a Rolls-Royce version of BMW's iDrive infotainment system and a satnav link for the eight-speed automatic transmission that knows what the terrain looks like ahead of you, and can therefore pick the right gear for where you're going. Clever stuff.

You can have either 20- or 21-inch wheels with run flat tyres, and the company claims that, thanks to all the extra panels and strengthening, it's the most rigid and secure four-seat convertible you can buy.

"Our new Rolls-Royce Dawn promises a striking, seductive encounter like no other Rolls-Royce to date, and begins a new age of open-top, super-luxury motoring. Dawn is a beautiful new motor car that offers the most uncompromised open-top motoring experience in the world. It will be the most social of super-luxury drophead motor cars for those who wish to bathe in the sunlight of the world's most exclusive social hotspots. Quite simply, it is the sexiest Rolls-Royce ever built. The name 'Dawn' perfectly suggests the fresh opportunities that every new day holds - an awakening, an opening up of one's senses and a burst of sunshine. In its tentative, inchoate, anticipatory state, dawn is the world coming to light from the ethereal dark of the night. The early-day chill of dawn provides an erotic tingle on the skin, awakening the senses and passions as the day begins. Like Eleanor Thornton, thought by many to be the inspiration behind the Spirit of Ecstasy, the Rolls-Royce Dawn will itself prove to be the muse that leads its owner to believe that at the start of the day, anything is possible" said Torsten Mueller-Oetvoes, Chief Executive Officer, Rolls-Royce Motor Cars.

No prices yet, but let's face it, it's not going to be cheap...