Hit US action show "24" returns to TV screens four years after its last season, with Kiefer Sutherland returning as fugitive counter-terror agent Jack Bauer.

The spy thriller moves to London for its first run-out since the end of season eight in May 2010. The new series, subtitled "Live Another Day," runs for 12 episodes, rather than 24 as previously.

Sutherland said he hopes viewers gripped by the show for nearly a decade will still be interested in the real-time action drama, a worldwide hit for broadcaster Fox.

"I'm cautiously optimistic, scared to death, and nervous. All of those things," he told Fox News ahead of Monday evening's two-hour premier.

"We had such a beautiful run for eight years, we had an audience who stuck with us through thick and thin, they were loyal and smart and they really supported us," he added.

The program and Sutherland have won two Golden Globes, in 2002 and 2004, as well as multiple Primetime Emmys and Screen Actors Guild awards.

The show debuted in 2001, with each episode depicting one hour of a 24-hour period in which Bauer races against the clock to thwart political assassination attempts and multiple terror plots.

The show claimed nine million viewers in its eighth season, well below its peak, according to the LA Times. Program makers announced last May that they planned to revive it.

The new series is filmed entirely in London, and takes place four years after season eight's finale, in which Bauer went into hiding following the killing of a Russian diplomat and assassin.

In April, online retail giant Amazon announced it had secured the streaming rights for "24," striking a deal with Twentieth Century Fox Television Distribution, as Amazon ramps up its battle against video giants like Netflix and Hulu.