They say the best way to keep your energy up is by getting enough sleep.
The pop princess appeared in need of a few z's after a dance rehearsal in Van Nuys. Even though she had a little caffeine on hand, it certainly didn't seem to be doing the job!
There are still a little more than two months before her big Las Vegas show begins, so there's plenty of time for Brit Brit to enjoy some rest and relaxation. But if we know our gurl, she'll be working her thang until the last minute.
We just hope she doesn't over-Work Bitch!
[Image via Miguel Aguilar/Pacific Coast News.]