Mia and her mom live in the former Chemical Engine Company 43 at 724 Brazil Avenue, in San Francisco, California. The two-story frame Mission Revival-style firehouse was built circa 1911 to provide fire protection to the Excelsior Homestead District. It was one of the first to leave behind the horse-drawn drays for the newly fashioned motorized apparatus shipped from the east. The retired firehouse was sold at auction in 1976. The private residence still retains a large hose drying tower in back.
When Mia accidentally sets the man's arm on fire, the flames were supposed to go out when he puts his arm in the ice bucket, but they didn't. Anne Hathaway panicked and threw the glass of water on it, which was not scripted.
Mia's cat, Fat Louie, was Anne Hathaway's pet in real-life. Four different cats played the role. One who allowed people to carry it, one who could sit still, another who would jump, and the last one, who sits on the envelope at the end of the movie.
Anne Hathaway had to wear a thick clip-in hairpiece to give her hair a much bushier appearance; the hairpiece became known as "the beast" by cast and crew. Her pre-make-over eyebrows took an hour to apply, as each tiny hair was individually glued on.
This movie was filmed on Stage 2 in Walt Disney Studios in Burbank, California, the same stage in which the film Mary Poppins (1964) was shot. The stage has since been named in honor of Julie Andrews, who starred in both films. The rental house that Julie Andrews lived in while filming Mary Poppins (1964) was lived in by Garry Marshall while filming this movie.
Garry Marshall wrote the retainer scene, after learning Anne Hathaway had worn a retainer when she was younger, but found it difficult to speak while wearing it. Hathaway brought in her old retainer for the scene.
One of the waiters in the scene when Mia drops something at the dinner says, "It happens all the time." The same actor played a waiter in Pretty Woman (1990), and also said the exact same line when Julia Roberts' character flings the snail and the waiter catches it. Both films were directed by Garry Marshall, as well as featured Hector Elizondo and Larry Miller.
In the book, Mia's father is not dead. Rather, he has testicular cancer. In order to avoid what Disney thought was a too adult topic, he was just written as dead in the movie. In the book, when Mia shoves the ice cream on Lana, her parents stick up for her. Also in the book, the plot of Mia's mother Helen dating her teacher is a much bigger deal.
During shooting of the tea scene in the garden, and the greenhouse scene, airplanes were flying over the area and interfered with the sound. When the scenes were finished, Garry Marshall gave Anne Hathaway and Julie Andrews awards for "best acting in airplane interference".
The neighbor, Mr. Robutusen (played by Patrick Richwood), also appeared in Pretty Woman (1990), as did Joe (Hector Elizondo), Charlotte (Kathleen Marshall), Paulo (Larry Miller), and the waiter (Allan Kent) in the scene in which Mia drops something at the dinner.
During the make-over, Paolo calls Mia's eyebrows Frida and Kahlo. Frida Kahlo was a Mexican artist who had a unibrow. Paolo also says, "If Brooke Shields married Groucho Marx, their child would have your eyebrows." Brooke Shields and Groucho Marx are both known for their thick, dark eyebrows.
Genovia appears to be a member-state of the European Union. The European Union Flag is displayed along with the Genovian Flag above the main door of the Genovia Consulate building, in the scene where Mia went to meet her grandmother the first time.
The boy at the baseball game who talks about a dental appointment on his cellphone (also the same boy who starts the: "Lana got coned!" chant after Mia throws an icecream cone) also plays the trainee security guard named "Lionel" in The Princess Diaries 2: Royal Engagement (2004).
When Lana says "There she is! That's Mia Thermopolis!" The photographer that says "looking for you!" and snaps a photo of Mia is Scott Marshall, Garry Marshall's son. He also plays the security guard "Shades" in The Princess Diaries 2: Royal Engagement (2004).
The trivia items below may give away important plot points.
Julie Andrews' jewelry and tiara for the final part of the movie was half a million dollars worth of real diamonds, on loan from Harry Winston. Anne Hathaway's tiara was made specifically for her, and was considerably cheaper - instead of diamonds, her tiara was comprised of cubic zirconia.
The on-screen relationship between Queen Clarisse Renaldi (Julie Andrews) and Joseph (Hector Elizondo) was not scripted. The dance scene, and the underlying affection was added by the two. According to Hector Elizondo, "We felt that a romance after fifty was important to tell, and it can be sensual and sexy while keeping your clothes on."
While filming the final celebratory dance scene, the Madonna song "Like A Prayer" was played on a boom-box to elicit natural dancing from the actors and actresses on-set (to be then dubbed over by the song that appears in the film's final cut). The Assistant Director had to do multiple takes of this scene, because the actors and actresses kept mouthing the words to "Like A Prayer" while on-camera.
For the first act of the movie, Queen Clarisse wears only black/dark outfits. Right before her dance with Joe, he says, "You've been wearing black too long." After the dance scene, Clarisse starts to add more color to her wardrobe. It is later revealed in the movie that her husband, King Rupert, had passed away the previous year. This means that at the start of the movie, she was still mourning his death. But as she falls in love with Joe, her personality once again becomes alive and colorful.
At the dinner, the old man and his wife sitting beside Mia that seem to be angry at each other, the wife also plays in The Princess Diaries 2: Royal Engagement (2004), as a maid to the uncle that is trying to take her crown.