On a certain level, most contemporary romantic comedies are all about the heroine's hair, and on that scale Ben Younger's likable "Prime" does very well indeed. Uma Thurman, as the newly divorced Rafi Gardet, sports angelic blond tresses that lead a complicated life of their own: alternately curly, smooth, fluffy, piled high, hanging long, intricately twisted, or at times strangely droopy, as if they could use a snack or a smoke. You wonder how she finds time to come up with all these styling options, what with love, therapy and a mysteriously glamorous career that involves standing around watching fashion shoots.

It would take a strong performer to stand up against that hair, and luckily "Prime" has one: Meryl Streep, as Rafi's therapist, Lisa Metzger. The cute premise here — and yes, it is pretty cute — is that Rafi's new, younger boyfriend David (Bryan Greenberg) is actually Lisa's son. Mother and son have different last names, and Rafi lies about him in therapy (she's worried that Lisa will disapprove of his age — 23 to her 37 — so she ups it a few years). It takes much of the movie for everyone to recognize the connection, with some funny complications along the way.

Movie review

Showtimes and trailer

"Prime," with Meryl Streep, Uma Thurman, Bryan Greenberg, Jon Abrahams. Written and directed by Ben Younger. 105 minutes. Rated PG-13 for sexual content including dialogue, and for language. Several theaters.

Thurman and Greenberg make a likable couple, though the real romance in the story seems to be between the camera and Thurman's cheekbones. But the movie really belongs to Streep. This revered dramatic actress is a top-notch comedian, and "Prime" gives her many (though not nearly enough) moments to shine.

When Lisa figures out that her precious son is dating this much-older divorced shiksa, her slippery face registers wonderment, horror and just a bit of amusement all at once — the situation, however dire, is kind of funny. And, once she's gotten her bearings, her sessions with Rafi take on a new shading. As Rafi gushes about her fabulous new love, Lisa interrupts, her voice elaborately casual: This young man — does he pick up after himself? Is he polite?

Younger, who made the 2000 Ben Affleck drama "Boiler Room," keeps the story appealingly light, though occasionally slipping into rom-com blandness. But Streep, beaming in her horn-rimmed glasses and spouting platitudes like "Focus on the now, for now," makes it all a treat.

Watch "Prime" and see a classic comic performance — and a few new hairstyle ideas for good measure.

Moira Macdonald: 206-464-2725 or mmacdonald@seattletimes.com