Britney Spears was casually dressed while leaving an office building in LA yesterday. She layered up in a gray hoodie for the outing and hid her mouth behind a pink retainer case as she made her way to the car. Britney has been spending the first weeks of Spring with lots of fun outdoor activities. In addition to cheering on her sons, Sean and Jayden, at recent soccer games, Britney sported a striped bikini during a Malibu beach day earlier this week. Her sexy swimsuit moment came on the heels of a photo shoot for Shape magazine, as well as big concert news. Britney announced on her Twitter page that she'll be joining Ryan Seacrest as a guest host for KIIS FM's Wango Tango concert on May 11.