Axis at Planet Hollywood headliner Britney Spears and her two sons Sean Preston and Jayden James stopped by the 4 p.m. Jabbawockeez show “Jreamz: A Journey Within” on Monday at MGM Grand. Britney posted a photograph of her sons in front of the theater as well as a video of them in the “America’s Best Dance Crew” Season 1 champions’ signature white masks on her Instagram.