Jennifer Lopez's stunning giant pink gown, but which star wore the look before? Then, Matthew McConaughey covered in blood after crawling from a flipped car. And, Backstreet Boys reveal the secrets that nearly destroyed the band. Plus, "Today's" Jenna Bush Hager is the frontrunner to replace Kathie Lee Gifford. What you never knew about her! Then, two over the top premieres! "Mary Poppins Returns" brings the magic, but "Aquaman" brings the dance moves! How Jason Mamoa's kids learned the routine on the spot! Entertainment Begins and Ends with ET!