BMW is teaming up with Lexus to try and create a car that will outperform Audi's R8. This was idea could have been concocted in reaction to Audi's comment that BMW doesn't have a supercar model for sale. A prototype has already been built but there doesn't seem to be anything more concrete beyond that. It is speculated by motoring.com that the supercar should be out in time for the Tokyo Olympic Games in 2020.
Motoring did a good job with the concept rendering and you can see the distinctly Lexus grille.