Breaking Britney news. The pop singer addresses her fans for the very first time and ET has new reporting on her health. Plus, Taylor Swift, Dwayne Johnson, Gayle King, Martha Stewart. Inside the event that's bringing together 100 of the most interesting and influential people in the world. Then, a beautiful new honor for Jennifer Garner. And, Chris Hemsworth and Scarlett Johansson dish new "Avengers: Endgame" details and wait to you hear what they say about each other. Entertainment Begins and Ends with ET.