The whole concept of Birdman starring Michael Keaton involves a star who used to play a superhero named Birdman try to make a new run at his career by heading to Broadway -- and Fox Searchlight has debuted one of the most unique viral marketing strategies for Birdman by releasing a fake trailer for the fictional 1992 film Birdman Returns (complete with aged footage), with Keaton's fictional character Riggan Thompson playing Birdman.

Perhaps the most interesting aspect of the trailer is its caption, which contains the #TBT ("Throwback Thursday") hashtag, and reads, "In 1992, Riggan Thomson makes box office history in Birdman Returns. It will be another 4 years before Riggan famously pulls out of Birdman 4 and disappears off the face of the planet until reviving his career on Broadway!"

It's certainly an intriguing viral trailer, given that Keaton actually was in a superhero film that released in 1992: Batman Returns. Furthermore, there are a few parallels between the Birdman Returns trailer and the Batman Returns trailer, including the stylizing of the credits and the somewhat heavy-handed narration. The logo displayed at the end is also very similar to the style of the logo for 1989's Batman, which was Keaton's debut as the Dark Knight.

Directed by Alejandro González Iñárritu and now in theaters, Birdman is a dark comedy that follows a washed-up and seemingly delusional actor famous for playing a superhero, who struggles to mount a comeback in live theater on Broadway. The film stars Michael Keaton, Zach Galifianakis, Edward Norton, Andrea Riseborough, Amy Ryan, Emma Stone and Naomi Watts.