Huh, I had no memory of him being in The Martian. To me he'll always be Troy. With a backup of Childish Gambino because I showed this clip to a friend:

https://www.youtube.com/watch?v=cMY9y-6W_fQ

And the friend said he resembled the musician, which is how I found out that actor also has a rap career.

Anyway, thanks for bringing this to my attention!