Filmmakers Des Doyle and Ryan Patrick McGuffey have said that they had almost given up on getting Joss Whedon in the film after trying for a year to reach him. Then one morning after leaving a meeting with Bad Robot they literally ran into him in the parking lot and pitched him then and there. Incredibly he agreed to take part.
However when they filmed his interview approx 2 months later (on the Monday morning after The Avengers opening weekend) they had literally just 1 hour to shoot before Joss was leaving for his first vacation in 2 years. Just as filming commenced workers started cutting down a large tree outside which lead to a traffic jam. Doyle was terrified that the sound from the interview would be unusable but had to proceed anyway. Remarkably the Sound Post-Production team in Dublin were able to remove all of the distracting background noise allowing the filmmakers to use Joss' interview.