According to Seth Rogen, Steve Carell was so nervous that the film would be shut down by the studio that he had the writers prepare a back-up version of the script that didn't contain a single word of profanity.
When Catherine Keener was cast, Steve Carell told Judd Apatow that her casting had legitimized the film's credibility.
To prepare for his role as Andy, Steve Carell lost thirty pounds for the role. Judd Apatow was originally nervous about the transformation, stating that he didn't think that "comedians wanting to look good is ever good for comedy." However, he gradually realized that Carell being "ripped" was a good idea, as it helped establish that Andy was only a virgin because he's shy and nervous, not because of his looks.