The diva may be tiny: a glimpse backstage revealed a petite woman far from the Amazonian stature her fame (and her historic towering over Sonny) project. But then everything about Cher defies expectations. With a Top 10 hit in every decade since the ’60s and a Best Actress Academy Award for Moonstruck, she has somehow entered the cultural zeitgeist as a punch line. "Actors don’t think I’m an actor and singers don’t think I'm a singer," she has lamented, with her trademark frankness (concluding, "and gay men think I’m their best friend"). And yet, the lady is a star.

As she takes leave of the stage at the age of 56, proclaiming her current "Living Proof" tour to be her swan song, she does so on her own terms. Those terms include Cirque du Soleil–style aerialists, dancers whipping across the stage in backflips, nine costume changes, video-documentary interludes, and the "many natural hair colors" promised at the opening of her FleetCenter extravaganza a week ago last Monday.

It was a grand show. From the Mongol-chic dancers swathed in fur to the Maori "tattoos" that decorated leotards, Cher outdid her own penchant for spectacle. There was fire (projected) and an animal act (a life-sized puppet elephant), and there was Cher, who appeared in the infamous butt-baring leather and stockings of her ’89 hit "If I Could Turn Back Time." Even for a performer who has proudly paraded her Vegas tendencies from early on, this was an all-out blowout. "Britney, J-Lo," she challenged jovially, "follow this show if you can, you bitches."

And the music? Cher’s throaty contralto, supported by two back-up singers and the same massive production values that make her so visually fabulous, is as strong as ever. After an odd opening (a ramped-up version of U2’s "I Still Haven’t Found What I’m Looking For"), she quickly hit her stride with her current dance hit, "Song for the Lonely," delivering it with all the oomph a contemporary torch singer needs. When she settled in for an oldies mini-set — kicked off by her first #1 hit, 1966’s "Bang Bang (My Baby Shot Me Down") — her dark voice sounded smoky but far from frayed.

The inevitable medley of beloved ’70s schlock ("Half-Breed," "Dark Lady," "Gypsies, Tramps, and Thieves") served up generous helpings of each song. And unlike many performers d’un certain âge, even when she turned the mike to the audience for the blockbuster "Believe," she handled all the hard bits herself. Were there backing tracks? Sure. Was there manipulation from the board? Probably. But beneath the fur and feathers, Cher remains a star.

Opener Cyndi Lauper continues to grow gracefully in her own way. She did the expected hits, a soulful "True Colors" and "Time After Time." But she also unveiled several promising new numbers, and the punk spirit of "It’s Hard To Be Me" reinvigorated yet another feminist anthem for the unacknowledged queen of grrrl pop.