Kevin Federline is deeply concerned about Britney Spears... The beloved pop star constantly worries her fans and inner circle with her erratic and scandalous behavior online. She posted that video of herself dancing in her home with what appeared to be dog poop all over the floor. Then Britney shared another dance video last week with a bandaged knee, telling followers she fell down the stairs at a friend's house and "it snaps out now and then" - though she's unsure if she broke it and no one knows if she even sought out medical treatment.