Well, who knew?
From the Gran Turismo website:
Honda Project 2&4 powered by RC213V / Gr.X
A new driving experience born in a collaboration between the Honda Design Team and Gran Turismo. This is a fusion of a motorcycle and car, with an aluminum-carbon composite backbone frame powered by a compact V4 engine from the Honda RC213V-S motorcycle. Its power to weight ratio is an impressive 1ps:1.88kg. If you remove the assistant side body cowling, you can also seat 2 people.