Not really a surprised, but its now official.
https://globenewswire.com/news-release/2018/06/05/1516731/0/en/Magna-to-Produce-the-new-Z4-for-the-BMW-Group.html
I ran across this older interview from Geneva, but I don't think it has been posted. Originally in Spanish, and translated by Google.
https://www.motor.es/noticias/entrevista-tetsuya-tada-toyota-supra-2019-201844546.html