What must it be like to be Britney Spears, to look outside and see oneself everywhere all the time, to look inside and see nothing? David Lynch would be hard pressed to come up with a better subject: a pop icon born of Disneyland hyper-realism and soft-drink wholesomeness and overlaid with the flimsiest sheen of robotic sexuality. Divided into two selves, the one on the surface obtuse and happy, the other all-knowing and unforgiving, both bound together in, as she introduces her latest tour, a "dream within a dream."

I hear Britney’s music as barely restrained terror — not as a teenage girl singing to an idealized boy but as a Socratic dialogue between an idealized pop star and her insatiable audience, a story about the infinite crushing gravities of desire swirling at the dark heart of that black hole we call pop stardom. Last Sunday at the FleetCenter, just after she finished a song called "What It’s Like To Be Me," Britney turned and looked herself square in the eye — that is, she looked into the eye of an exact life-size image of herself on an oversized video monitor. Then, as a new song played, Britney and pre-recorded Video Britney enacted a duel of a dance, a mirror image in double time. Soon the pre-recorded Britney disappeared and was replaced with a live feed of the actual Britney standing in front of the video screen, and a trail of duplicate images zoomed off, a visual echo of infinite surrogate selves dissolving behind her into darkness.

As a pop-music performance, Britney Spears’s concert last Sunday was merely trite; though much improved, she is still an unconvincing dancer, and I suspect she didn’t do much singing. As the confession of a secret self in the language of artifice, however, it was heartbreaking and scary. The rainbows-and-ice-cream Britney smiles and listlessly hits her cues, but she is a woman literally at war with her own image.

She emerged a vampire in a black trenchcoat with a blood-red lining, flanked by eight dancers in French Quarter zombie garb worthy of Anne Rice — a Queen of the Damned singing a revamped "Oops! I Did It Again." She closed with a "Baby, One More Time" envisioned as a baptism cum wet-T-shirt contest. Time and time again, she gave us nightmarish metaphors for the psychic distortion of teenage megastardom: the clockwork ballerina trapped in a music box (the set-design premise for a medley of her most tragic songs, including "I Was Born To Make You Happy" and "Lucky"); the imagemaker trapped within her own image; the dreamer imprisoned in the dream. During "(You Drive Me) Crazy," her dancers circled her with trapezoidal mirrors and ensnared her in a net; for "Overprotected," a video monitor showed her dancing behind bars while the real Britney danced in a cage of laser lights. The real and the imagined, the actual and the simulated, swirled until they became indistinguishable.

At the end, Britney leaves the stage. We see her on a video monitor, waking with a start from sleep, telling her audience what it’s just seen is a dream, a ghost, a fantasy. The camera pulls back and she’s seen trapped in a droplet of water against a black background. And this time she doesn’t wake up.