James Franco completely transformed into Tommy Wiseau while making The Disaster Artist - as readers can see in our exclusive clip from the film. Franco has received a lot of praise for his portrayal of Tommy Wiseau in The Disaster Artist, even winning a Golden Globe for the role.  Franco didn't so much play Wiseau as he became the writer/director/producer/actor, mastering not only the man's mysterious accent but also the specific mannerisms, body language, and laughter that have become associated with Wiseau. And matching him step for step in every recreated scene from The Room along the way.

Franco also directed the film, imbuing his docu-dramedy with an interesting bit of irony by directing himself in a very good movie where he plays the real life director (at least according to the credits) of a famously bad movie. Not only that, but Franco directed while still speaking in Wiseau's accent, maintaining the voice through each day of filming.

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Now in our exclusive behind the scenes clip, fans can finally see how deeply Franco went playing Wiseau. The moment that prosthetics went on his face - rendering the actor nearly unrecognizable as himself and creating a so close it's eerie resemblance to Wiseau - Franco would only speak with Wiseau's voice, no matter what he was discussing or working on.

The video also shows Franco speaking as Wiseau to the real Wiseau while filming the cameo which played over as The Disaster Artist's post-credits scene, earning Wiseau's praise for mastering the accent that the real Wiseau claims to have dropped. The video also includes the reactions of several of Franco's co-stars and long time collaborators, including his brother Dave Franco, Dave's wife Alison Brie, and Franco's friend Seth Rogen - all of who marveled at how strange it was to see Franco in the makeup and hear him speak in Wiseau's voice.

Tommy Wiseau in The Room and James Franco in The Disaster Artist

The Room turned the real Wiseau into a cult icon, as he continues to show up at screenings for his movie as it still plays in theaters with a fair amount of audience participation. Since The Disaster Artist came out in theaters Wiseau has been enjoying a rise in his celebrity and has taken to social media not only to reach out to his fans, but everything from campaigning to play The Joker to asking Mark Hamill to help get him a ticket to the Oscars. He also reteamed with his longtime friend and The Room co-star Greg Sestero for the movie Best F(r)iends, which Sestero wrote for Wiseau. And he is working on bringing The Room to Broadway.

Meanwhile, Franco has taken a step back from the public eye since winning his Golden Globe - due to being accused of sexual misconduct. So perhaps it's a good thing that Wiseau is taking up the slack while Franco takes a break from the public. After his transformation in The Disaster Artist, some people might not even be able to tell the difference between them.

MORE: THE ROOM INTERVIEW: TOMMY WISEAU & GREG SESTERO

The Disaster Artist released on Blu-ray March 13, 2018.