Article continues below advertisementBritney Spears' kids made a rare appearance on social media.Sean Preston, 20, and Jayden James, 19 - the pop star's sons whom she shares with ex-husband Kevin Federline - stepped out for to cheer on their cousin Maddie Watson, 17, at her high school baseball game.Article continues below advertisementIn a heartwarming photo shared on Instagram on September 17, Maddie - daughter of Jamie Lynn Spears and Casey Aldridge - smiled in her athletic gear, even with her right arm in a sling.