The two apparently bonded over a mutual connection to James Dean during the development of The Disaster Artist, and that also appears to have blossomed into a bit of a friendship (even if Franco would not let Wiseau actually speak on the stage).
The connection between Tommy Wiseau and James Franco (similarly known as a bit of an eccentric at times) is something that has become well-established through the lead-up to The Disaster Artist, as well as its release.
Wiseau has spoken at length about his feelings towards The Disaster Artist, and he also says that he believes that it has his “99.9 %” approval — he only criticizes the short-range football tosses.