The recent rumors have proven to be true.  "24" starring Kiefer Sutherland has been cancelled.  The show is currently into its 8th season and will premiere the final episode on May 24th. 

"This has been the role of a lifetime, and I will never be able to fully express my appreciation to everyone who made it possible," Kiefer told Access Hollywood. "While the end of the series is bittersweet, we always wanted '24' to finish on a high note, so the decision to make the eighth season our last was one we all agreed upon. This feels like the culmination of all our efforts from the writers to the actors to our fantastic crew and everyone at FOX."