With the addition of Tony Kushner and Jeanine Tesori's musical, Caroline, or Change, which recently began previews at the Eugene O'Neill Theatre, Broadway now has three sets of that staple of 1960s pop radio: the girl group. Reimagined theatrical versions of The Supremes and their like can currently be seen harmonizing and executing synchronized choreography in Hairspray, Little Shop of Horrors and Caroline, or Change.

All of the trios perform some crowd-pleasing vocal histrionics, but otherwise serve different functions in the plot. In Little Shop, the oldest show of the three, the three singers—teasingly called Ronnette, Crystal and Chiffon, after three popular mid-60s girl groups—act as a sort of Greek chorus. They comment on the action of the play, sing several narrative numbers, and interact with the story's characters. By show's end (spoiler alert!), they're the only folks left undevoured by the musical's carnivorous plant.

In Hairspray, the group is called the Dynamites. Far from real, they walk out of a billboard as a fantastical element of frumpy Edna Turnblad's lavish makeover in the number, "Welcome to the '60s."

Finally, in Caroline, a trio of African-American actresses embody a radio—one of many anthropomorphized elements in the musical. (Other actors impersonate the moon, a washer and a dryer.)

Girl groups thrived in the '60s, some emerging from the Motown stable of artists, others groomed by pop produce Phil Spector. Most were composed of African-American singers, who attempted to build an aural bridge between white pop and black soul music. The most successful by far was Motown's The Supremes, which racked up a dozen number one singles with Diana Ross as a lead singer. Also with Motown were the Martha and Vandellas, led by Martha Reeves. The Ronnettes, a trio led by Ronnie Spector, were probably Phil Spector's most famous group. Though musical-theatre makers have chosen the three-girl make-up to add a little soul and verve to their shows, quartets were just as common in Motown. Among the more famous foursomes were The Chiffons, The Shirelles and The Shangri-las. The Crystals, meanwhile, had five members.