The upcoming sports car from BMW has been spied again during cold weather testing in Europe.

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Compared to the prototype spied at the Nurburgring last September, this tester has dropped some of its camouflage from the front bumper, production tail-lights (though still partially concealed under the disguise) and a new rear diffuser that features squared-off tail-pipes.

The rest of the car is still concealed underneath a heavy black-and-white camouflage, though the overall shape is clearly distinguishable to the closely-related Toyota sports car prototype also spied this week.

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Dubbed the 'Z5', BMW's new sports car will succeed the now-discontinued Z4, and share its underpinnings and most of its engine line-up with the upcoming sports car from co-developer Toyota - which could revive the iconic Supra badge.

Both cars are said to share the same platform, rear-wheel drive, and feature a range of four- and six-cylinder turbo petrol engines under the bonnet. Additionally, the Toyota may offer a hybrid drivetrain, though it's unclear whether BMW will offer an electrified model.

Also on the cards for the Z5 is the option of the company's xDrive all-wheel drive system, though this has not been confirmed.

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The Z5 is expected to be solely offered as a roadster, while the 'Supra' is likely to only be made available in  coupe form.

In terms of timing, the BMW sports car is expected to be revealed later this year, before going on sale in 2018.

Stay tuned to CarAdvice for more updates.

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Click the photos tab for more images of the 2018 BMW Z5 prototype