After six seasons as the first-billed lead on "The Vampire Diaries," Nina Dobrev announced she would be leaving -- though the show would go on to a seventh season. "TVD" has since been renewed for a Season 8.
Christopher Meloni made an abrupt exit after the Season 12 finale of "Law & Order: SVU," and the show seemed doomed without one half of the Stabler-Benson partnership at its heart, but with Mariska Hargitay still on board, the show has just been renewed for a Season 18.
"Sleepy Hollow" shocked fans when it killed off its leading lady Nicole Beharie, the first billed actor on the show, in the Season 3 finale. The series has not yet been renewed for Season 4, but producers have already reassured fans they will continue without Beharie's Abbie Mills if good news does hit.
When "Homeland" began, it seemed to revolve around Claire Danes' obsession and relationship with Damian Lewis' maybe-terrorist character. But after Lewis' Brody was killed off in the Season 3, the show continued, and was recently renewed for Season 6.
Before Season 3 even ended, "The Blacklist" killed off its leading lady Megan Boone, and her FBI character Liz Keen. This could course-correct itself, since Boone is out due to real-life pregnancy, but for now, producers are insisting she's really dead. It has already been renewed for Season 4.
"The X-Files" without Mulder or Scully? The quintessential partnership show did just that when David Duchovny left the show in Season 8, forcing Gillian Anderson's Scully to find a new partner. The show managed to go one for one more season ... Plus 2 movies and a revival, with Duchovny back on board.
Ahead of a Season 9 pickup, ABC confirmed "Castle" leading lady Stana Katic would not return -- but Nathan Fillion was already in negotiations to continue to play the titular role. Producers have already confirmed plans to reconfigure the show around Castle.
After 11 seasons, Shondaland drama "Grey's Anatomy" shocked its fans to the core when it killed off Patrick Dempsey's Derek Shepherd. Meredith Grey persevered, and so did the show, which has been renewed for Season 13.
Amid rumors of backstage drama, "The O.C." killed off its leading lady Mischa Barton, who played the troubled Marissa Cooper, in the Season 3 finale. The show lasted just one more season, with Autumn Reeser's Taylor Townsend being brought in to "replace" the dearly departed Marissa.
In one of the most high-profile and explosive separations between shows and their lead actors, Charlie Sheen didn't just burn his bridge with "Two and a Half Men" after 8 seasons, it was more like a nuclear blast. But the show survived, brought in Ashton Kutcher, and lasted 4 more seasons, for a total of 12.
Continuing her rocky relationship with Darren Star post "Beverly Hills 90210," Shannen Doherty's Prue Halliwell was killed off after 3 seasons on "Charmed." Rose McGowan was brought in to fill the void, and the show lasted for 8 seasons total.
After seven seasons as the lead on 'The Office," Steve Carell and his character Michael Scott said goodbye to the NBC sitcom. The show devoted multiple story arcs to finding his replacement, and ended after two more seasons, for a total of nine.
"One Tree Hill" fans were skeptical when it was announced that leading couple Chad Michael Murry and Hilarie Burton would not be returning to the show after Season 6, but Peyton and Lucas did indeed ride off into the sunset, and the show continued on for three more seasons without them.