Brit Brit just opened up her residency show at Planet Hollywood in Las Vegas.  There were a bunch of stars in attendance like Katy Perry, John Mayer, and Miley Cyrus.  Photos were taken showing Katy seemingly less than enthused.  However, Miley seemed to be into it.

Or at the very least she seemed to be into Britney's backup dancers.

Miley Cyrus At Britney Spears Concert