My prom was OK but I had hoped it would be more fun. So, too, with "The Prom."

Just as "Singin' in the Rain" works best as a movie, the hilarious but insider-y musical "The Prom" made more sense on Broadway, since it skewers stage egos.

Meryl Streep and James Corden star as narcissistic show people. They're belting out a number that celebrates how they are "Changing Lives" by playing little-known historical figures Eleanor and Franklin Roosevelt, when they get the bad news that their show "Eleanor!" is a bomb. Needing good PR, they pivot to a story from Twitter about an Indiana high schooler whose prom was canceled because she wanted to bring a female date. So they gather some friends to make her a prom.

Streep, wearing a J. Roy Helland-created wig that splits the difference between Liza and Patti, is a self-deprecating performer anyway, and she embraces the chance to poke holes in her own ego, incorporating jazz hands and popped-hip poses in even the most casual moments. Nicole Kidman, as a dancer who's never made it out of the chorus, has less to do, but her walk, with "Fosse hands" swaying back and forth behind her butt, is a thing of beauty.

Corden, who's straight, has caused controversy for his caricature of a gay showbiz vet who embraces the chance to make over a drab Midwestern teenager. I think he's fine — it's an affectionate caricature, and his performance resembles that of the (gay) actor who originated the role on Broadway — because he approaches lines such as "I'm as gay as a bucket of wigs" with care and wit.

As director, Ryan Murphy situates "The Prom" in a space that looks like the real world if it had a few more sequins and follow spots. But he's not good at dance sequences; the performers' legs are out of frame and when we want to see Streep executing the finale's athletic choreography, we can't see her at all. Also, whereas the stage version had the perfect balance of sentiment and sarcasm, Murphy tips the movie too much toward the former.

The problem is what Chad Beguelin and Bob Martin have added to their script in adapting it for the movie. They've given the three leads the kind of big, dramatic monologues that fill in back stories but are really here to attract top actors who are eager to dive into meaty material.

Those scenes play fairly well — although Corden's weepy take on his family turning their backs on him is over the top — but they run counter to the fizzy fun of the production numbers, they supply redundant information we could have guessed, and they throw off the balance of "The Prom," which is supposed to be about the Indiana teen whose name I have not mentioned because the movie constantly forgets about her.

As a result, a movie that's supposed to poke fun at showbiz egos ends up catering to them instead.

Chris Hewitt • 612-673-4367

The Prom
⋆⋆½ out of four stars
Rating: PG-13 for suggestive references and language.Streaming: Netflix.