The actor is well known for his leading roles as Iron Man and Sherlock Holmes.
However, the 46-year-old has revealed that working on the 2010 comedy was one the most enjoyable processes of his career.
The movie was directed and written by The Hangover director Todd Phillips and co-starred Zach Galifianakis.
"I am crazy about this movie,” he told the LA Times. “I just love it so much. Like Bradley Cooper in The Hangover I'm playing an aspect of Todd Phillips, an uptight, anxious, controlling aspect. The missus has seen this side of me too. This became one of the most privately joyful experiences in history. It had what all of my favourite comedies have: a real emotional resonance.”
On Friday, Robert will receive the 25th American Cinematheque Award, which honours his contribution to cinema.
The actor has been nominated for an Academy Award twice. The first was for his portrayal of Charlie Chaplin in Richard Attenborough’s 1992 film Chaplin. The second was for his supporting role in the Ben Stiller comedy Tropic Thunder.
The film is a parody of Hollywood. Read more