Twelve years after he portrayed the iconic role of 'Kirk Lazarus' in Tropic Thunder, Robert Downey Jr is facing a public backlash over his 'blackface' in the movie. Downey and Tropic Thunder started trending on Twitter after being criticized for knowingly darkening the colour of his skin for the film. Released in 2008, Tropic Thunder, directed by Ben Stiller is a satirical action comedy film which revolved around the making of a Vietnam war movie.