Britney Spears launched her two year Vegas residency at Planet Hollywood last night, drawing rave reviews and celebulous attendees.

The famous fan who made her presence most known was—no surprises here—Miley Cyrus. During Brit's performance of "Till the World Ends," Cyrus started dancing, well, as if the world were ending. Front row, too; isn't she lucky...

Give it a watch here, and tell us you don't kind of fall in love with Miley's crazy once again.

See Miley perform on her own tour by checking out the schedule here and getting your Miley Cyrus tickets now!