The 2023–2024 season is the season of diegetic songs, with a wealth of diegetic music factoring in to some of the hottest tickets in town. But just what is a diegetic song?

Similar to the show-within-a-show trope, diegetic music is music within a show that the characters can hear: the characters know they are singing, and so does  anyone else observing them onstage.

Diegetic songs step away from the oft quoted musical theatre cliche of breaking out into song when words are no longer enough to communicate a character's inner state. While a song like "Soliloquy" from Carousel perfectly encapsulates a character's inner state of mind, Billy does not actually realize he is singing as he bounds up and down the shoreline. Instead, the music is pouring forth from him unconsciously, giving the audience a peek into his internal monologue. 

The exact opposite is true for diegetic songs: The characters are singing within the narrative of the show, and all the layers of artifice a performance requires fold themselves into the rendition. In short, the audience observes an actor playing a character that is themselves performing. Convoluted, yes?

Not really. While laying out the definition for diegesis can be confusing, in practice, you're likely already very familiar with the technique: a large swath of your favorite musicals likely employ diegesis, even if it is only for one or two songs within a wider, non-diegetic narrative. While some shows, like Dreamgirls, are almost entirely diegetic (in the stage version of the classic, more than 70 percent of the score exists within a performance context, rather than a non-diegetic context), many shows employ brief moments of diegetic music for effect: think Wicked and the ensemble singing "Dear Old Shiz" or "The Sparkling Diamond" number in Moulin Rouge!

This season, a large number of shows are employing diegesis techniques to tell their stories—among them Cabaret, Stereophonic, and Merrily We Roll Along.

Cabaret is often considered one of the greatest diegetic musicals of all time. Depending on how it is directed, just about every song within the show can be diegetic: while the numbers performed within the Kit Kat Klub are inherently diegetic, more interior songs like "Perfectly Marvelous" and "It Couldn't Please Me More" have, in various productions, been staged in such a way that the characters are aware that they have broken out into song and dance.

As a show-within-a-show narrative, Cabaret is a classic example of how diegetic music can support a narrative. While Sally Bowles' mother may not literally think she's living in a convent, the way an actor plays the song "Don't Tell Mama" can tell a viewer a lot about Sally both as a person and a performer. The same is true of the Emcee, with the perfected and practiced behavior of his persona proving all the more powerful for the brief moments we see it slip mid performance.

As Redmayne previously told Playbill: "Within 'I Don't Care Much,' I wanted you to hear him move from one voice into the other within the same song. So he's sort of demonstrating to the audience the power he has in his passivity, just to keep changing the versions of himself."

With the hotly anticipated revival set to begin performances on Broadway April 1, many fans of the Kander and Ebb classic are eager to see how the more interior songs will be handled: Will Fraulein Schneider and Herr Schultz consciously dance with a pineapple, or will they be floating on a dream? What of the Emcee's final reprise following the closure of the Klub? While the West End production certainly offers clues, we are eagerly awaiting the curtain rise on Broadway to see if any changes have been made in crossing the pond.

Diegetic music often has a home within straight plays as well: the use of sound to create the world of a play is deeply influential—just as a character may hear a bird outside their window, so too can they hear a record on a turntable.

David Adjmi's play Stereophonic, fresh off its hit Off-Broadway premiere, takes things a step further, bringing audiences into a band's various recording sessions in the 1970s. Through the piece, viewers are invited to witness the artistic process and the evolution music undergoes before being recorded, seeing some tracks evolve from vague chords to power ballads in almost real time. While the lyrics within the songs often relate to what we see play out on stage, they are rarely character revelations: audiences see every bit of sweat that goes into crafting the perfect sound, rather than allowing the song to flow from the characters minds with pure perfection.

That's also partially why many of the songs head in Stereophonic are snippets instead of full songs. 

READ: How the Company Cast Recording Documentary Inspired Stereophonic

Oftentimes, this is where the distinction between a musical and a play with music is drawn. Whereas musicals use songs, and the lyrics within them, to reveal inner truths that would be lost without the score, plays with music are able to stand as pieces of drama with just the text. Granted, plays with music miss a significant piece of their magic when silenced, but you are still able to ascertain the core narrative and character motivations within the piece without its score (should that be necessary).

When a character sings in Stereophonic, it is an artistic expression, but it is not the sum of who that character is: that can be found in the show's delightfully specific scene-work. Put it another way—swap the show's composed score for the classic Fleetwood Mac record Rumours and the narrative would still play out almost the same (though we don't recommend it because Will Butler's songs are some of the best original music of the season).

It certainly isn't an all or nothing game, of course. The list of shows that engage with moments of diegesis is endless, and it can often flesh out otherwise non-diegetic worlds.

Consider Merrily We Roll Along, now back on Broadway. Written by Stephen Sondheim and George Furth, the majority of the musical is non-diegetic; Charley doesn't actually realize he's singing a patter song during "Franklin Shepard, INC" However, the show does engage with diegetic songs when necessary to enrich the world of the show, sometimes even in the middle of non-diegetic numbers.

"Opening Doors", which sees the main trio (Frank, Charley, and Mary) hard at work, is mostly non-diegetic. There are two sequences, however, that are pure diegesis: composing duo Frank and Charley's audition for producer Joe, and the auditions they hold for their revue (the "Who wants to live in New York" portion).

In both instances, it is important for the audience to see the different between the unfiltered trio they are bearing witness to during the non-diegetic sequences, and the more filtered and presentational versions of themselves that the characters show others during diegetic performance. When Joe gives them feedback on their song, he has to have actually heard it.

The same is true for Frank and Charley's performance at a party in Joe's home, the song "Good Thing Going." Without the use of diegetic music, the audience would not be able to see the difference between how Frank and Charley work a room, one of the first major fissures within their working relationship. Sondheim was careful to employ diegesis in exactly the amount necessary to show this to the audience, without the show wholly turning into a diegetic musical à la Cabaret. 

Diegetic music is an incredibly powerful technique when employed with care—it can be used widely to great effect, or slightly with serious implications. But what matters most is that it is used intentionally. Drift too far from the storytelling core, and a show can shift from the musical genre to that of a revue, loosely grouping together songs without enough narrative to tie them together. 

Employ the technique with care, and it can be an immensely valuable part of a composer's arsenal.