Britney Spears -- Inside Out Girl

12/3/2009 2:03 AM PST BY TMZ STAFF
Considering all the people paid to watch her back, you'd think one of 'em would have told Britney Spears her sweater was on inside out.

Britney Spears: Click to watch
28-year-old Brit Brit got her b-day shop on with BF Jason Trawick yesterday at Fred Segal -- where the paps actually sang "Happy Birthday" to her ... without the assistance of a backing track.