Another two actors have been cast for the upcoming fifth season of 24.

Syriana star Jayne Atkinson has been signed to play Karen Hayes, a "heavy-handed" Homeland security official who "is sent to CTU to clean up a situation".

Stephen Spinella, a Tony Award winner for Angels in America, will play Miles, her subordinate.

"We feel lucky to be working with so many great actors," said exec producer Howard Gordon. "Each of these newcomers, as well as the previously announced cast additions, will help deliver the thrill ride 24 fans have come to expect."

The new season premieres Sunday, January 15 on FOX and early February on Sky One in the UK.