The Audi TT Sportback perhaps qualifies as the major surprise of the Paris Motor Show as it was one of just a few uncertainties to be revealed. Although if you've been following Audi's strategy over recent shows, it should come as no surprise at all.

The TT - once the brand's standout, but very singular product - has entered its third generation with a much wider mission. The new generation was introduced at the Detroit show at the start of this year, in slightly bizarre, allroad shooting brake preview concept. As we said at the time "strip it of the cladding and give it a coupe roofline and you've got the new TT". Then, hey presto, come Geneva, and just that happened - with the new, third generation TT launched in its traditional 2+2 coupe format.

READ: Audi TT (2014)

The first major surprise came in China, when a TT SUV concept was shown at April's Shanghai show. Clearly, far from a single model, this was Audi hinting that the TT might become a wider range of cars within the Audi brand. Much as Fiat is doing with the 500 (500L, 500X, and so forth).

And so to Paris, where we see the predictable launch of the production TT roadster, which you'll be able to buy from early next year. But also this TT Sportback concept.

So what is it? Well, it's still a TT coupe, but one that's got an extra set of doors, and (slightly) more space in the rear seats and the boot than the standard TT. Why's Audi doing this? Because it believes there are many people who really like the idea - and the sporty image - of a TT, but need more space than the coupe offers. And because of the equity of the TT brand someone who might today buy an A3 saloon, or A5, might choose one of these instead - and it will command a premium over regular A models, in both its price and image. Which is good news for Audi.

Pocket-lintTT Sportback 8 copy

While it could be argued that Audi is diluting the TT name by pursuing this strategy, it's hard to quibble with the way this car is executed. It's instantly recognisable as a TT as all the car's design signatures are there. It's beautifully resolved - and in fact, the window line has extra space to breathe, so much so that it's better resolved than the regular coupe. It arcs in one, long, accelerating line, unlike the new coupe window line that has introduced a bizarre kink at the base of the C-pillar.

And unlike BMW's GT models, the TT Sportback avoids the awkward "humpback" look in side-on profile. Those TT-signature wheel arch extensions give it a fabulous, purposeful stance to the way it sits, too.

Then you open the door and are greeted with that same interior found in the 2-door TT coupe. Which, for the money, is the best car interior in the world right now - certainly in terms of its design detail and the integration of advanced interior technology.

If you're wondering why we're talking about this concept car like it's a production car, that's because we believe it is close to being so. Regular show goers can easily spot the lashed together concepts that are forever to remain on the drawing board, from the ones that are previewing a production car. And the TT Sportback has all the hallmarks of the later. The way it's put together looks production-ready. And if we were to bet, we'd say this car is a sure bet to join the coupe, and the SUV model in a three-car TT range.

Come 2016 expect to be able to buy it - minus the bling grille, wheels and the weird blue bits in the lights - and in an engine range that will mirror that of the TT coupe.

Stretching the TT too far? Not a bit of it - from where we're sitting the Audi TT Sportback is a beautifully executed piece of design that delivers a clear and unique appeal.