As the production could do nothing about inquisitive crowds watching them while they were filming in Rome, they actually set up a phony second unit a little further away, hired several girls in bikinis and several older women dressed as nuns and pretended to be filming takes for the film, while the main unit got on with their business largely undisturbed.
After the success of Shaun of the Dead (2004), Simon Pegg was asked whether he was going to be pursuing a career in Hollywood, to which he laughed and replied "It's not like I'm going to be in Mission: Impossible III".
Tom Cruise allegedly threatened to cancel publicity for the film if Comedy Central rebroadcasted the Trapped in the Closet (2005)' episode of South Park (1997) that satirizes Scientology and mocks Cruise's sexuality. Comedy Central is owned by Viacom, which is the parent company of Paramount Pictures, and Mission: Impossible III was distributed by them. The episode was indeed pulled off the air. Trey Parker and Matt Stone, creators of South Park, said they were called by Comedy Central and told that the episode would be pulled off the air, and they were also told not to say anything to anybody about it.
With a budget of $150 million, this is the most expensive movie ever undertaken by a first-time feature film director.
Dan Mindel: (At around thirty-five minutes) The film's cinematographer appears as a doctor talking to Julia in the hospital.
Michael G. Kehoe: (At around one hour and eleven minutes) The Craft Service crew member appears as Mike the hospital employee, when Ethan enters the hospital, and he's in search for his wife, and heads for the front desk where Mike is seated.
J.J. Abrams: The director can be seen in the hospital when Ethan is looking for his wife. He is also the voice on the phone talking about a free trip to Mexico.
J.J. Abrams: [Kelvin] (At around 31 minutes) The postcard that Agent Farris sent Ethan Hunt from Berlin is addressed to H. Kelvin. Harry Kelvin was J.J. Abrams' maternal grandfather, and as a tribute to him and his influence in the director's life, Abrams includes his name in every project he directs.