During a recent livestream, Gabe Newell’s son Grey revealed that a few years ago that they visited Japan to meet with Nintendo executives about a project. Newell said..
My dad was talking to him [it isn’t clear whether Newell is referring to then president Satoru Iwata or Miyamoto] about some joint project. I think it was about the original Wii that ended up not happening.This was like probably seven years ago. It was super casual.
While it’s unknown what was discussed, we did find out that Grey got to play Super Mario Galaxy for Wii with Shigeru Miyamoto.