Due in the autumn, it's the first phase of Up variants that will also include a 108bhp sporty Up GT version and, in the longer term, a fully electric model.
The five-door is no bigger than the three-door, the engine line-up is the same and there is a relatively modest 375 premium. That means prices will start from around 8375 for the entry-level 59bhp version; the more potent engine, a 74bhp version of the same 999cc motor, will continue to be offered on higher trims.
What's it like inside? From the driver's seat, you won't notice any difference from the three-door which means the Up has the beating of anything sub-10k when it comes to the choice of materials and build quality.
The controls are laid out neatly, the driving position is hard to fault, the seats are a little flat but comfortable nonetheless and all of the hard plastics in your line of sight are either textured, or finished in gloss 'piano' lacquer. Even the removable sat-nav and infotainment system (a 275 option, or standard on the top-spec model) is clear and easy to use.
The view from the rear is pretty similar, too, although you won't have to struggle to get there in the first place. The rear doors make access easier than it is on the three-door, and once there you'll find enough headroom for six-footers. There's just about enough leg- and kneeroom for four people of that height, although they'd need to be comfortable with each other's company.
The Up's boot capacity is unaffected by the extra doors, so it stays at 251 litres or 26 litres more than a Hyundai i10's. That rises to a genuinely useful 951 litres if you fold down the seats.
What's it like to drive? The good news is that the five-door Up retains all of the driving qualities of its less accessible sibling. The three-cylinder engine is smooth, the five-speed transmission is precise and slick, and the steering is linear and nicely weighted not too heavy for urban manoeuvring, yet not too light for occasional motorway use.
That balance sums up the overall set-up, in fact. The ride is well judged for the Up's most likely environment around town because it's firm, with supple damping. The 74bhp motor feels strong enough for a mix of mostly urban and occasional A-road use, too.
We also had a chance to try the five-door equipped with a five-speed automatic transmission, which will become available around the same time as the five-door models, carrying a premium of around 600-700.
To be precise, the gearbox is a robotised manual system - similar in concept to those employed by Citroen, Peugeot and Smart - and while it undoubtedly has similar benefits (cost and weight, mainly), it also has the same drawbacks. Shifts take an age and it's hard to stop the Up from lurching back and forth as you try to maintain smooth progress; we wouldn't recommend this option unless you absolutely cannot live with a clutch pedal.
Should I buy one? The five-door Up is a strong addition to the line-up. It doesn't add a great deal of extra practicality over the three-door, but it does make it noticeably easier to access the rear cabin, and is every bit as good to drive.
If you're after an Up, and are intending to use the rear seats for anything more than occasional use, we'd consider this option as money well spent.