Starring Meryl Streep, Pierce Brosnan, Colin Firth, and Stellan Skarsgí¥rd.

There was one obvious question raised while walking into Mamma Mia!: how in God’s name could the often-melancholic star of Silkwood and Sophie’s Choice pull off shaking her middle-aged ass while belting out ABBA’s ditzy disco standards? For the first half-hour of the movie based on the megahit musical, you can’t help focus on the way Meryl Streep is working so hard to convince you she can, she really can, sing, dance, and play Donna Sheridan, the earthy owner of a dilapidated Greek hotel-taverna.

But—mamma mia!—resistance is futile. Around the time the veteran Hollywood super trouper leads a girl-powered dance parade to the island docks, dammit if she hasn’t won you over.

Make no mistake: Mamma Mia!’s true draw is the infectiously fizzy songs and lyrics by Benny Andersson and Bjí¶rn Ulvaeus. First-time director Phyllida Lloyd safely sticks to the same structure as the musical (which she also once helmed), but she manages to give the material something approaching, well, depth. Freed from the limitations of the stage, the film’s postcard setting of cliff-side terraces over a sparkling Mediterranean sea gives it the feel of a fairy tale come to life.

As with the stage production, the story is a ridiculous excuse for stringing together a bunch of ABBA hits. Young Sophie (Amanda Seyfried) is about to get married at her mom’s Greek hideaway and wants her dad to walk her down the aisle. The only problem is that her mother was never sure which of three guys was the father, so Sophie invites them all to the isle to try to figure out who it is. Pierce Brosnan and Stellan Skarsgí¥rd give game performances in somewhat thin roles, with Colin Firth’s anal-retentive Harry the comedic highlight.

But it’s Streep who eventually gives the film its heart, whether she’s singing a tender goodbye to her daughter as she helps her prepare for her wedding or givin’ ’er in the cathartic blast to lost love that is “The Winner Takes It All”. Ironically, her emotionally nuanced performance makes other cast members seem out of place, especially Christine Baranski and her gaggingly campy numbers.

Still, camp is what Mamma Mia! is all about. The best advice is to drop all your prejudices about over-the-top musicals and join the hen party; otherwise, you’ll end up yelling “S.O.S.”.