Don'tcha just love movies about show business? This R-rated (language and alcohol) romantic dramedy features guerrilla concerts which last only until the cops arrive, a failed partnership which sets a frustrated music producer adrift, and enough gorgeous shots of New York City to satisfy even Woody Allen. Director John Carney ("Once") sets his players on rooftops, in parks and alleys, under bridges and near well-known landmarks; this is an ode to the city and a tribute to the creative souls who make our music.

Here is a gentle, upbeat, unexpectedly sweet piece about the music business; we see performances in small clubs and big theaters, with music professionals who range from corporate officials to social networks gurus.

We enjoy:

• * Keira Knightley ("Anna Karenina") as a would-be singer/songwriter dumped by her partner as his career unexpectedly takes off and she's left in his wake.
• * Adam Levine ("American Horror Story") is her dumper who succumbs to the siren song of success. How do you spell R-E-M-O-R-S-E?
• * James Corden ("One Chance") is an old friend who offers her shelter and a shoulder to cry on.
• * Mark Ruffalo ("Iron Man 3") as a has-been music producer who first alienated me until I saw the creative side of him, then he became someone I could root for.
• * Catherine Keener ("Captain Phillips") is his soon-to-be former wife, dealing with the detritus of her relationships. I LOVE the way she and her husband click into what is obviously an old habit of sharing a smoke and hiding it from their daughter.
• * Hailee Steinfeld ("Ender's Game") is the angry daughter of our recently split couple; but she gets seriously good advice from the would-be singer.
• * Mos Def (as Yasiin Bey "Life of Crime") is the corporate official who asks our hero, "What have you done for us lately?
• * CeeLo Green ("Sparkle") is one of our hero's former clients who has never forgotten who helped him when he needed it the most.

Do you think our two leads might make beautiful music together? Seriously? I think I failed to mention that this is unpredictable. You'll have to see for yourself. And you'll have a clearer picture of what a gifted music producer can bring to the table.

Let me mention: No sweaty bodies, no vehicular mayhem, no guns and no blowie uppie stuff. That's probably good enough for many of you, right? It is for me; I liked it.