Birdman beats Boyhood to win Best Picture at the Oscars 2015

Film was directed by Mexican Alejandro Inarritu

Michael Keaton stars as a washed-up superhero actor in Alejandro González Iñárritu's self-reflexive film 'Birdman' (YouTube)

It was a night of double joy for Mexican director Alejandro Inarritu when he won Best Director only to then see the film he had directed named as Best Movie.

His film, Birdman, a satire of showbusiness and fame, won the Academy Award for best picture, the film industry's highest honour.

The film from Fox Searchlight Pictures portrays a washed-up former superhero actor, played by Michael Keaton, and his struggle to make a comeback in a Broadway play.

It stood out among the eight nominees for appearing to be filmed in one long continuous shot, the Associated Press said.

Eddie Redmayne won best actor with his painstaking portrayal of physicist Stephen Hawking in "The Theory of Everything", robbing "Birdman" lead and former superhero actor Michael Keaton of a big comeback moment.

Inarritu thanked the star-studded audience for seeing his "crazy film."