Britney Could Go All Night Long

We all know that when it comes to raising hell (if not to showing up for court dates), Britney Spears is a marathoner -- but could the same be true for her work habits?

Her latest video director, Wayne Isham, tells People, "Her endurance was remarkable, as we had a long day. She almost outlasted me, which is amazing! It was a pleasure to work with her again." Unlike some of her other work excursions, she actually performed to expectations -- such as they were.

"Piece of Me" -- in which she rips the paparazzi -- debuted over the weekend.

Matthew McConaughey -- Ultimate Fighting guy? Apparently so, says his rep, who said yesterday that his chestacular client was injured while prepping for his role in "The Grackle."

Matt was training Ultimate Fighting Championship-style, says Alan Nierob, when he cut his face. Last week, pap shots showed Matthew wearing a bandage over his left eye while riding in the passenger seat of a car. He was also, reportedly, wearing a shirt.

Newly reduced Ashley Tisdale -- just on this side of surgery to correct a "deviated septum" -- had to ditch a pair of concerts in Miami and Philadelphia because of post-surgical issues.

The Tizz actually managed to sing at the Z100 Jingle Ball concert in New York on Friday, unveiling her hot-off-the-scalpel honker to the world, but then couldn't make her weekend gigs. As she explained to fans in her blog, "the deviated septum was more significant than we originally thought, so the healing process is taking longer."