Although not confirmed, rumours indicate that the new car will be branded as the Z5. Not only does the new badge indicate that the new car will be larger in most dimensions than the Z4, but that it will also feature higher pricing than the current vehicle.
It hard to discern any of the car's styling details, as this prototype has been fitted with plenty of slimline false body panels and is clad in a layer of swirly camouflage.
Nonetheless we can see that the new vehicle will stick with the same basic layout as both generations of the Z4 thus far: seating restricted to just two seats, a long bonnet and a short rear deck.
In a break from the second-generation Z4, it looks as though the new vehicle will revert back to a fabric top, lowering the car's complexity and weight in one move.
Interestingly, the fabric top on this prototype doesn't feature an aperture for a rear windscreen, while the boot lid seems to sport a clamshell design.
Under the skin, the Z5, or whatever it will be called, will ride on a rear-wheel drive sports car platform that's being co-developed with Toyota.
The Japanese brand will use the underpinnings for a car that's being billed as the spiritual successor to the Supra, with rumours strongly tipping that its vehicle will feature a hybrid drivetrain.
It's expected that the Z5 will be offered with a choice of turbocharged four-cylinder and, potentially, six-cylinder engines.
Some rumours indicate that the Z4's successor won't emerge until 2018, by which time the second-generation Z4 will be in its tenth year. Other chatter suggests that the Z4 replacement could make its debut as early as this year.
Locally, sales of the Z4 have slowed down to a trickle. In 2015, 65 new Z4s found homes down under, down from 83 in 2014. By way of comparison, 235 copies of the Mercedes-Benz SLK were sold in 2015, down from 475 the year before.