Alex Trebek reveals he's battling cancer. The beloved "Jeopardy" host and his very personal message to his fans. Breaking his silence, R. Kelly denies sexual abuse allegations in explosive interview with "CBS This Morning" host, Gayle King. What Gayle only told us after the interview and what's next for the singer? Then, "Riverdale's" tribute to Luke Perry and the lost roles you may not remember. Plus, Taylor Swift gets candid about her biggest concern about touring. Plus, Ben Affleck, Selena Gomez, Demi Lovato. Three stars on the road to recovery. ET reports on how they are working to get healthier. And, ET's with the "Brady Kids" for an exclusive tour inside "A Very Brady Renovation." Entertainment Begins and Ends with ET.