Fans of NBC's 'Up All Night' well know that the series has endured a troubled road to success, re-tooling its premise for a second season and most recently making the decision to shift from a single-camera to a three-camera studio audience sitcom, losing series creator Emily Spivey in the process. That change has now claimed yet another casualty, and it's a big one. Series lead and upcoming 'Anchorman 2' star Christina Applegate has decided to leave the series entirely, but will NBC replace her or cut their losses altogether?

'Up All Night' has been through quite a bit of upheaval in its two seasons, but the latest shocker could well finally put the series to sleep. Per Deadline, we've learned that series star Christina Applegate has reportedly quit the series altogether, just prior to its imminent re-tooling into a three-camera studio audience sitcom.

“It’s been a great experience working on 'Up All Night,' but the show has taken a different creative direction and I decided it was best for me to move on to other endeavors,” said Applegate in a statement. “Working with Lorne Michaels has been a dream come true and I am grateful he brought me into his TV family.  I will miss the cast, producers and crew, and wish them the best always.”

Deadline also reveals that NBC is considering a replacement for Applegate, potential candidates including former 'Friends' and Showtime's 'Web Therapy' star Lisa Kudrow. Applegate's co-stars Will Arnett and Maya Rudolph have yet to comment on the shocking exit, nor has NBC made a formal declaration of how the series will proceed under its new format.

Well, what say you? Should Christina Applegate's exit from 'Up All Night' be the final nail in the baby coffin? Is the series worth keeping on with a new lead in the three-camera format?