Disney's latest animated film Frozen has been compared to classics like Beauty and the Beast and The Lion King—and with good reason. The songs in the film are heart-swelling and evocative of the type of stuff you might remember from childhood. To learn more, we had the husband and wife songwriting team Robert Lopez and Kristen Anderson-Lopez walk us through the creation of some of the movie's songs. 

Frozen, which opens tomorrow, tells the story (loosely based on a Hans Christian Andersen tale) of two sisters, Anna (Kristen Bell) and Elsa (Idina Menzel), the latter of which has complicated magical powers that allow her to create snow and ice. If that sounds like standard Disney fare, you'd be right. And the Lopezes, of course, know their history, tapping into the legacy of The Little Mermaid and Beauty and the Beast lyricist Howard Ashman, who helped revive Disney animation in the eighties and 90s. "I’m not going to lie. We had a little thing we would say ‘What would Ashman do?'" Kristen told the Wire.

"There’s no such thing as a new song without antecedents, and if you don’t listen to them you’re dooming yourself," said Robert, who co-wrote The Book of Mormon and Avenue Q. "You’ve got to kind of know what’s been written before in order to write something different." Here, Robert and Kristen walk us through some of the antecedents for five songs. 

Frozen Heart 

The film opens with "Frozen Heart," a mood-establishing tune sung by workers cutting through ice. As the Lopezes pointed out, it has origins in a type of song used in past Disney films, like the "Song of the Roustabouts" from Dumbo and "Fathoms Below" from The Little Mermaid.  "I guess we were in a meeting, and I kept saying: ‘if we could just have a song which basically said the ice is beautiful and dangerous and set up a little mystery,'" Kristen said. Robert also noted that the "masculine energy" of the song establishes the expansiveness of the story. "I think that’s why 'Fathoms Below' is in The Little MermaidIt’s telling the boys this is going to be a story with songs, but there’s going to be something in it for everyone," he said. "It’s not just a princess movie. And Frozen isn’t just a princess movie. It’s got a lot of action and fun and entertainment and stuff like that, and 'Frozen Heart' kind of tells you there’s going to be some violence in this story.

For the First Time in Forever

Princess Anna's big, early song is For the First Time in Forever, a declaration of hopes and dreams as her castle opens its doors for the first time for her sister Elsa's coronation. To write Anna's big number, Robert and Kristen looked at "traditional 'I Want' songs," Robert said. "We looked at The Sound of Music, we looked at 'Part of Your World' and 'Belle.'" Initially, the Lopezes thought they had written a "keyboard driven song," Robert explained. It wasn't until arranger David Metzger came along and made it sound "orchestral" that they realized just how traditional it was. "It’s just soaring," he said. 

In writing for Bell, Kristen said: "We knew we were going to harness her incredible dichotomy of this classic, pure, ingenue voice and her modern, funny girl sensibility." Hence, "For the First Time in Forever" has lyrics like: "Don't know if I'm elated or gassy/ But I'm somewhere in that zone!/ 'Cause for the first time in forever/ I won't be alone." 

Love Is an Open Door

This pop number was actually a "real challenge" for the Lopezes, who had to use it to make it believable that the lonely Anna would agree to marry the dashing Hans (Santino Fontana) after only a couple of hours spent together. "We thought of it like the best first date ever," Robert said. "Honestly, I’ve dated this guy," Kristen added, before quickly noting: "before Robert of course. You have that date where you play mini golf, and you play skee ball, and you tell each other everything, and then you’re in a bar at three am singing karaoke, and you’re convinced that that person is the love of your life forever." To put the characters at ease, Robert said, they made the song as "casual" as they could, and listened to music like Coldplay and Bruno Mars. "Those songs that make you just feel like our love is one with the universe," Kristen explained. "That sort of feeling like all is well, I never have to worry about anything again—that’s what we want to feel in that chorus. But of course it’s a Disney movie and it’s happening way too early, so you know something’s going to happen.

Let It Go

The big, belting Idina Menzel ballad was the first song the Lopezes wrote that stayed in the movie, and it makes sense. It's the centerpiece song, the song that encapsulates the heart of the movie. It was also a moment that they knew was staying in the story. "We thought every audience loves a transformation, every audience loves a makeover," Robert said. "This would just be the perfect opportunity to write a big power ballad for Idina Menzel." And Menzel's voice, which boomed into legend when she sang "Defying Gravity" during her run in Broadway's Wicked, makes complete sense for the song and, Kristen said, the character. "Idina’s voice perfectly captures who Elsa became," she explained. "Because Idina’s voice on the low end has this vulnerability, it’s like a fragile child almost when you put her in the lower ranges, and then when you bring her up high she has this incredible, iconic Broadway power. We wanted to write something that played to that classic instrument that comes along once in a lifetime."

To craft her big number, the Lopezes listened to a lot of their "favorite singer-songwriters, who write about ways that secrets or shame or expectations keep them from being as powerful as they could be," Kristen said. She rattled off a list of names: Aimee Mann, Tori Amos, Adele, Avril Lavigne, and Lady Gaga. Robert popped in and mentioned Katy Perry as well. 

In Summer

Robert called the first draft of this ditty sung by Olaf the snowman (voiced by Book of Mormon vet Josh Gad) "obnoxious," and Kristen described it as "Paul Simon meets 'Hot Hot Hot.'" Though a lot of the lyrics from that original song remain in the final product, it was a realization about the character that helped the Lopezes find what ended up in the film. "Once we realized poor Olaf was very naive, like a child, we knew we had to go to a more classic naive sound," Kristen said.