Codenamed G29, the new roadster has been developed in a joint project with Toyota, although the two models to emerge from the shared process – the Z4 and the Japanese firm’s Supra – will be substantially different. BMW’s offering will be a convertible only; the Toyota will be sold as a coupe.

The car’s looks and proportions stick pretty closely to those previewed on a concept that was revealed at the same American event last year. There’s a particularly short overhang at the front end, and a visible decrease in wheelbase compared with the outgoing Z4. Here’s another video of its premiere…

The images also confirm that this Z4 has a folding fabric roof (it opens in around 10 seconds), eschewing the aluminium hard-top of the outgoing generation on grounds of complexity, cost and weight. The new car’s total kerb weight is said to be around 50kg lighter than its predecessor’s.

The model unveiled in Pebble Beach is the Z4 M40i First Edition, described by BMW as “a taster of the forthcoming on-road debut of the new roadster”. It’s powered by a 3.0-litre straight-six petrol engine, producing 340bhp – enough to take the new drop-top from 0-100kmh in 4.6 seconds.

BMW is being coy on releasing many technical details – they’re being held back until late September – but the firm has confirmed that M40i edition has electronically controlled dampers, upgraded M Sport brakes and an M Sport differential. It also says the Z4 will have a 50:50 weight distribution.

The line-up of powertrains is likely to include a 2.0-litre four-cylinder petrol, possibly in a couple of states of tune, along with at least one more version of the straight six. We’d expected a plug-in hybrid version to follow later in the car’s life, too – and there could even be a fully focused M version of the car, because BMW hopes a more involving dynamic experience will allow the Z4 to grab some sales from the Porsche 718 Boxster.

The cabin shows a further evolution of BMW’s cockpit layout, with a newly designed fully digital instrument panel, and a ‘fared-in’ infotainment system that’s clearly angled towards the driver. The usual iDrive rotary controller is mounted on the centre tunnel beside the controller for what is likely to be an eight-speed automatic transmission. A manual gearbox is likely to be offered too, Auto Express understands, but only with selected engines.

The Z4 is due on sale in the UK next spring. There’s no word on pricing or specs, but we’d expect the range to start with 2.0-litre models at around £30,000, rising to around £48,000 for the M40i seen here.

Ed’s note: Nice one BMW, however, I think it looks a little too much like something Fiat came up with in 2015, the 124 Spider… anyway, please revive the Z8 next! – Chris Wee.

BMW Z4 Photo Gallery (all images courtesy of AutoExpressUK)