If there was any doubt that a BMW Z4 successor is coming, then these photos should eliminate any doubts. These are the very first spy shots of the BMW Z5 Roadster which was caught testing in the night at around -25 degrees Celsius. The images show a heavily camouflaged prototype with the typical proportions and short overhangs of a BMW roadster. Judging by the photos, the dimensions of the alleged Z5 Roadster are larger than the current BMW Z4 while featuring a soft top compared to the hard cover found on the Z4.

At the 2015 Geneva Motor Show, Klaus Frohlich, BMW head of R&D told the press that not only a Z4 replacement is in works, but also confirmed that it will be developed together with Toyota. The two companies have been working on three sports cars for years now. BMW and Toyota have been tight-lipped about details but the two companies say their partnership will last until at least 2020.

Toyota and BMW outlined plans for the sports car in early 2013 and said in November 2014 that they’d reached the concept phase for the vehicle after completing a technical feasibility study. The manufacturers have declined to specify where the model might be built or when production would start. Sources say the car in question for BMW would be a Z4 replacement, and will most likely use a turbocharged four-cylinder engine.

With first test mules hitting public roads now, the Z5 is likely to be unveiled by 2018.