Yeah, that’s the one I was going to mention, and the other non-qualifying number is “Dancing in the Dark”. And I want to second the part about how everyone should see it. Really.
What about “A Funny Thing Happened on the Way to the Forum”? IIRC, that one is “a play within a play” in its entirety.
Not that I recall, at least not the film. I haven’t seen the stage version. Although the main character is aware that he’s in a play, and breaks the fourth wall.
I’ve only seen the stage play. I saw it 48 times though. I saw a lot of classical musicals 48 times, my first job out of college was as lighting director for a dinner theater that specialized in classical musical comedy.
But the opening number - Comedy Tonight - sets it up as a play within a play.
“Nothing that’s grim, nothing that’s Greek, she plays Medea later this week”. That’s the line that stuck with me.
So the opening number establishes that they all know they’re in a play. But -except for the main character- they all stay in character the entire time and don’t step in and out. Not sure that counts. Especially since Comedy Tonight wasn’t in the very first rendition, it was added in tryouts.
But, in order to meet the qualification otherwise, you have to find a show where the cast slips in and out of character but no one ever sings when they’re off-stage/not performing. That’s tough. Maybe a work that’s a biography or drama about a singer would fit. Most musicals with plots aren’t that limited, though.
Can’t Stop Singing from Teen Beach Movie
That’s why I specified the movie: that song was dropped. Fosse’s goal was to stage all the numbers where it was natural for people to be singing.
In the store the other day I heard That Thing You Do on the PA system.
Took me back to [del]1964[/del] 1996.
I think the move That Thing You Do! qualifies. A ton of music. Not all of it replays of the title song. (Which doesn’t have the “!”, btw.) Here’s a listing of the soundtrack.
My favs are Shrimp Shack by Cap’n Geech & The Shrimp Shack Shooters and I am Spartacus. 
Some or all of the title song is heard 11 times in the movie.
It peaked at number 41 on the Billboard charts yet somehow made it to a store music playlist.
But they do in & around music stores? :dubious:
You’ve never been to a street festival? I’ve seen singing and dancing around those (okay, maybe not to that degree of professionalism, but still…)
As would Motown: The Musical. And while I haven’t seen it, I suspect that Ain’t Too Proud would also qualify.
I think all the songs in The Gang’s All Here (1943) are performances – either onstage or at other functions. Even “A Journey to a Star” is sung by Alice Faye primarily to demonstrate her singing ability to James Ellison, not really to advance the plot.
The same goes for the 1954 A Star Is Born – the musical numbers are all performances. Judy Garland sings two songs to James Mason privately (“Someone at Last” and “It’s a New World”), but they’re still performances that aren’t required for the plot.
Why wouldn’t four singers break into a little song?
My wife and I loved Sing Street and wish it had been a huge hit. There is one scene where the song they’re performing is greeted with a lot better response than it actually had been, but for the most part it was all in context.