Ferrari just got even more exclusive. The Italian luxury automaker is gearing up to start production on its invite-only supercar known as the Ferrari Sergio, and only six people will be able to get their hands on one.

The concept car, unveiled at the 2013 Geneva Motor Show, was designed in collaboration with Italian firm Pininfarina, and each model is expected to sell for millions, though Ferrari would not disclose an exact price.

But if you wanted to be one of the lucky six, you're too late as Ferrari has already pre-sold all the Sergio cars. Long-standing Ferrari clients are the only ones who got the invites.

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A spokesperson from the automaker told CNBC the final orders are being confirmed and production will start "shortly", with the aim of delivering the final product to clients next year. Ferrari will have to make changes to the design unveiled at the Geneva Motor Show in order to comply with road laws so the design is likely to be different from the original concept which had no windshield or mirrors.

Ferrari has made a point of being exclusive by capping the number of vehicles it makes each year to 7,000 and the move has paid off financially. The brand, owned by Fiat Chrysler Automobiles (FCA-IT), reported revenues of 1.3 billion euros ($1.65 billion) in the first half of the year, a 14.6 percent rise from the same period in 2013.

The company also has a "one off" program where enthusiasts with deep pockets can design a bespoke car from start to finish and have it made at Ferrari's Maranello headquarters. The Sergio buyers' identities have not been revealed but in the past big names like Eric Clapton have purchased custom made cars.

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The Sergio is based on the Ferrari's 458 Spider mechanical base and technologic components. The doors rise up rather than open outwards and the company said the car can accelerate from 0 to 100 km/h in less than 3.4 seconds.

Ferrari has pursued a similar exclusive approach with another car in its range – the LaFerrari supercar . Only 499 are being made, and after its debut at the Geneva Motor Show last year, over 1,000 people had already requested the car. But similar to the Sergio, you don't choose the car, Ferrari chooses you.