One of Britney Spears' boobs popped out while she performed at a concert. Like Janet Jackson before her, Britney was also wearing a very tight fitting PVC outfit onstage.
Britney's boob popped out when the arm of a dancer caught her outfit, sending her tightly compacted, ample bosom spilling out.
Oddly enough, this happened a month ago. Britney's boob incident was only reported now because the photographer noticed it while developing the film. Source