19 things you probably didn't know about 'The Princess Diaries'

In a bonus clip from "The Happy Days of Garry Marshall," Andrews said that when she first met with Marshall to discuss the film, he asked her a lot of questions about Genovia.

When he asked what she thinks they'd make in the country, she said, "Making it all up on the spur of the moment, I said, 'Well I think they'd grow beautiful pears ... and the nuns would probably make lace.'"

She continued, "Well, we had pears all over the set, and lace all over the place as well."

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In the film, Mia's family rules in the country of Genovia. Although the country isn't real, in "The Princess Diaries" world, Genovia is a European country.

Outside of the Genovian consulate building in San Francisco, both Genovia's flag and the flag of Europe are flying.

The late music legend Whitney Houston was a producer for both "The Princess Diaries" and "The Princess Diaries 2: Royal Engagement."

Although the late René Auberjonois was the voice of Mia's dad Philippe Renaldi, the photo that Mia keeps on her desk actually appears to be a picture of Hathaway's real father, Gerald Hathaway.

Elizondo also told the San Francisco Chronicle that Joe wasn't originally supposed to be such a prominent character.

He and Andrews helped persuade Marshall and the writers that their characters should end up together.

"We thickened the soup a little bit for the adults," he said. "In the original script, he was just a guy who drove a limo. But slowly we evolved this other character. That came from a reading: Julie and I looked at each other and said, 'Hmm, you're cute.' We liked each other very much."

Queen Clarisse Renaldi's lead security official and love interest was played by Golden Globe-nominated actor Héctor Elizondo.

If he looks familiar to fans, they may have seen him in nearly any other film directed by Marshall, including "Pretty Woman," "Runaway Bride," and "Valentine's Day."

According to The San Franciso Chronicle, Elizondo said he thought he and Marshall worked well together.

"We complement each other," he said. "Some call him the king of schmaltz. He loves schmaltz. And I tend not to go in that direction. I add another ingredient, something very realistic. We intersect, and it works somehow. Go figure it."

This was the second movie Andrews filmed on soundstage 2 — and, in honor of her association with the set, Disney renamed it after her.

Andrews had previously filmed "Mary Poppins" on the same soundstage in 1964 before starring as Queen Clarisse Renaldi in 2001.

In a 2001 interview with Screen Slam, Hathaway said Marshall allowed the actors to give plenty of creative input into the film.

For example, Hathaway inspired the broken pre-makeover hairbrush and the pore strip her character wears in the movie.

Marshall made allusions to "Pretty Woman" throughout "The Princess Diaries," including using the same actor to play the waiter.

In both films, the leading actress has a scene where she accidentally breaks a wine glass, and in both films, the waiter who cleans it up is played by actor and writer Marvin Braverman.

In "The Princess Diaries," Baverman even tells Hathaway's character, "It happens all the time," when she apologized for the mess.

Marshall's granddaughters, Lily and Charlotte, have cameos in the films.

The duo starred as autograph seekers in the first film and appear in the second film as Princess Camille and Princess Grace, respectively.

Marshall's daughter, Kathleen, also appears in both films as Charlotte Kutaway, the queen of Genovia's secretary.

In a 2001 red-carpet interview, Marshall said he made "The Princess Diaries" for his granddaughters, saying the film was a "Pretty Woman" (1999) for teenagers.

Marshall was actually the director of the rom-com "Pretty Woman," and he made several references to the film in "Princess Diaries."

According to Bustle, Marshall appears at the end of the first movie at the annual Genovia independence ball.

On her website, Cabot wrote that parts of "The Princess Diaries" were actually inspired by her life, namely the fact that her mom dated one of her teachers after her dad died.

Cabot wrote she also used to imagine that her "real" parents were royalty and thus Mia Thermopolis was born.

"The Princess Diaries" soundtrack also featured classic late-1990s/early-2000s songs like "Wake Up" by Hanson, "Little Bitty Pretty One" by Aaron Carter, "Split Personality" by Pink, "What Makes You Different (Makes You Beautiful)" by the Backstreet Boys, and, of course, Moore's live performance of "Stupid Cupid."

California rock band Rooney has a strong connection to the world of Mia Thermopolis.

Frontman Robert Schwartzman played her unrequited love interest, Michael Moscovitz. Although the rest of the band doesn't appear in the film, their songs were used for the scenes with Schwartzman's on-screen band.

Schwartzman didn't appear in the sequel because he was touring with his band — which just so happens to be the same way his character was written off the film.

Instead of hiring an actor to play the part, they just got Willie Brown, the then-mayor of San Francisco, to do it.

Brown can be seen in arriving at the Genovian Independence Ball toward the end of the film.

Although Hathaway had previously appeared on the TV series "Get Real," the Meg Cabot book-turned-movie was her first Hollywood film.

She told Glamour magazine in 2013 that starring as a princess in the hit film caused her to be categorized as a "good girl" in the industry, a label she spent years trying to break free of.

2001 was nearly two decades ago, so you may have forgotten that both Mandy Moore and Sandra Oh were featured in the film.

Moore, who is a lead character on the award-winning show "This Is Us," played mean girl Lana Thomas, and Golden Globe-winner Sandra Oh played Vice Principal Gupta.

During an interview in "The Happy Days of Garry Marshall," Hathaway said that her dramatic fall on the bleachers in the scene with Heather Matarazzo (who played Lilly) was totally unplanned.

"I turned really fast, slipped on a puddle, and just I mean fell. I mean just absolutely fell, and burst out laughing and kept going with the scene. Never thought about it again," she said. "All of a sudden, like six months later it's in the trailer ... He kept it because it was a charming moment."