Jack is back, and now there's a trailer as proof of life. 

Check out the new "24: Live Another Day" clip below, in which exiled ex-CIA agent Jack Bauer (Kiefer Sutherland) must prevent the assassination of the U.S. president James Heller (William Devane) in London, not to mention a potential world war.

Watch the clip here:

Taking place four years after the series finale, the 12-episode "Live Another Day" also features returning stars Mary Lynn Rajskub, plus Benjamin Bratt, Yvonne Strahovski, Giles Matthey and Gbenga Akinnagbe on Team CIA. The cast also includes Michelle Fairley, Stephen Fry, Michael Wincott, Tate Donovan and Branko Tomovic.

"24: Live Another Day" premieres Monday, May 5 on FOX.