Britney Spears will have a big reunion today ... with her kids. Britney and Kevin Federline have joint custody of 13-year-old Sean and 12-year-old Jayden. The arrangement has been that she gets them 3 days, he gets them 3 days, she gets them 3 days, he gets them 3 days, and so on. Also, Taylor Swift is dropping her new single at midnight ... and she says the new track is all about embracing your individuality, celebrating it and owning it.