Musicals are a genre with certain identifiable stylistic conventions that have been cemented over time. Part of the reason that musicals exhibit these consistent patterns is because the vast majority of the successful musicals since the dawn of the sound era were all produced under one roof: MGM Studios. From the late ‘30s to the ‘50s, the genre’s top directors - Charles Arthur, Stanley Donen, Gene Kelly, and Vincente Minnelli - all worked under a branch of production at MGM under producer Arthur Freed and they likely had the same loose guidelines to follow. Additionally, many musicals that made their mark in the movies - like Brigadoon (1954), Kismet (1955), West Side Story (1961), My Fair Lady (1964), Funny Girl (1968), Hello, Dolly! (1969), Oklahoma! (1955), The Music Man (1962) - made their way from Broadway and retained its theatrical traditions in their DNA.

One of the primary conventions of a musical film is the idea of integration, or the idea that songs should fit naturally and logically into a narrative - when characters spontaneously erupt in song and dance, it should be as natural to them as speaking.

Early musicals often made this convention more readily acceptable for audiences by crafting stories around diegetic songs, as in the backstage musical. In MGM’s early Broadway Melody series, and the Busby Berkley productions at Warner Brothers, the plot centered around performers on a stage, so that whenever their characters were singing, it would make sense within the confines of the plot.

One can see evidence of the gradual transition from films that rely on diegetic songs to the more sophisticated integration of music in a film like Meet Me in St. Louis (1944), in which some of the musical numbers make sense within the context of the plot (Judy Garland and Margaret O’Brien singing “Under the Bamboo Tree” to entertain house guests) and some don’t (“The Boy Next Door” or “The Trolley Song” are non-diegetic expressions of uncontainable feeling). More interestingly, Meet Me in Saint Louis has numbers which fall into a grey area: In the opening of the film, Judy Garland strolls in singing “Meet me in Saint Louis” and is joined by her older sister on the piano, before their father storms in and tells them to “turn off that racket.” This scene could be taking place outside the context of reality, but when we see the dad (a character who sings no musical numbers in the film) interrupting them, we understand the scene differently: it’s just two girls getting carried away as they are humming a tune.

By the mid-20th century, musicals had become commonplace, and audiences no longer needed a logical explanation for the interpolation of songs in the narrative. However, modern-day musicals face the same challenge as early musicals of getting audiences on board with characters expressing themselves through song.

Hollywood rarely produced musicals during the 70s, 80s and 90s. When the genre experienced a resurgence in the 21st century, modern-day audiences, eagerly awaiting musicals, were not familiar with the form. In order to bring back the genre, Hollywood has had to gradually revert from the integrated musical back to the backstage musical like High School Musical (2006) and Dreamgirls (2006). Exceptions to the rule, where Broadway-style musicals have been accepted by audiences (as in the cases of 2005’s Rent and The Producers), have been more acceptable as integrated films because they were musicals on Broadway prior to becoming films and didn’t tamper much with the source material. At the same time, it’s telling that neither of those two films got great reviews.

When a musical does fully embrace an integrated formula, as in the case of Moulin Rouge! (2001), its aesthetics tend to come across as over the top. Although the sheer ambition of the film was enough to get the film an Oscar nomination - and a subset of people hail the film as genius - the critical reaction and response from many moviegoers at the time was polarized.

Chicago (2002), on the other hand, was able to win an Oscar for best picture as a musical and inspire the unofficial headline in Hollywood, “The musical has officially been revived.” The film is credited with reinventing the musical for the 21st century because it was able to make cinematic musical comedy go over with audiences while preserving the fun of the original integrated musical by setting the musical numbers in the mind of the lead character.

In the last decade, perhaps because more musicals have been released and the average American moviegoer might be more musical movie-literate, integrated musicals have seen a moderate resurgence. Films like Across the Universe (2007) and Into the Woods (2014) have garnered positive critical responses and strong box office returns. While the movie musical is unlikely to regain the dominent position it once held in Hollywood, the recent shift back to integrated musicals suggest that the genre is once more becoming popular with mainstream audiences.