Britney Spears back to performing? The new message she has for her fans. Plus, Scarlett Johansson engaged? How the ?Avengers: Endgame? star found love on ?Saturday Night Live.? Then, James Corden spilling secrets about his epic ?Carpool Karaoke? with Celine Dion. And, we're rocking out in London with the cast of ?Rocketman!? Entertainment Begins and Ends with ET.