The "Avengers: Endgame" world premiere takes over Hollywood. Chris Hemsworth, Robert Downey Jr., Chris Evans. What the stars are only telling ET about Marvel's blockbuster movie. And, who may have let a big spoiler slip to ET's Kevin Frazier. Plus, why the star power on the 'purple carpet' could rival the Oscars. Then, Britney Spears's sister breaks her silence on the "Free Britney" movement. And, George Clooney's surprising new job? What we just learned. Entertainment Begins and Ends with ET!