As if her costumes weren't revealing enough, Miley Cyrus hit the stage in her skivvies on Sunday night.

The attention-grabbing 21-year-old missed a costume change before performing her tune "23" in Milwaukee, so she headed out on stage in just a striped pair of underwear and a bra.

"Not a new outfit for 23," she tweeted. "I didn't make my quick change and I couldn't not come out for the song so I just had to run out in my undies :(. "

She added: "Never happened to me before. ... "Show must go on :(. "