During pre-production, Robert Downey Jr. took up an office space next to Jon Favreau's office. Downey wanted to be more involved in the film's screenwriting process. Downey was reportedly also very involved in the writing of 'Iron Man 2.'

Downey's only writing credit is on a documentary he scripted and produced in 1993 called 'Last Call' in which he does reports and interviews with other stars about the Democratic National Convention in 1992. For 'Iron Man 2', Downey Jr. recommended screenwriter (and Jennifer Aniston boyfriend) Justin Theroux, who wrote 'Tropic Thunder' with Ben Stiller.

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