Canadian actor Kiefer Sutherland is seen attending the season eight premiere of his TV drama 24 in New York in January. (Charles Sykes/Associated Press)

The long-simmering idea for a movie adaptation of Fox's counter-terrorism TV series 24 is a step closer to execution, after 20th Century Fox hired a screenwriter to pen a script.

The studio has hired Billy Ray to script a 24 feature film story, with the pitch reportedly involving sending series star Kiefer Sutherland's Jack Bauer character to Europe to unravel some nefarious plot, according to reports in Hollywood trade media.

Ray's screenwriting credits include the political thriller State of Play, the Second World War POW drama Hart's War and the in-air suspense story Flightplan. He also wrote and directed both the Stephen Glass journalism drama Shattered Glass and Washington-set docudrama Breach.

The 24 creative team — including Sutherland, who is also an executive producer — have floated the feature film idea for years, especially as the show continues to fare well in international markets.

However, they have also repeatedly emphasized that a full-length movie would likely have to wait until the series ends because of its demanding schedule for both writing and production. It's felt that the show's regular hiatus does not provide enough time to write and shoot a feature-length film.

The late-2007 Hollywood writers strike postponed 24's seventh season, but producers managed to complete the two-part TV movie 24: Redemption, which ultimately nabbed several Emmy Award nominations.

The eighth season of 24 began in January and ends in May. Fox TV has yet to announce whether it will schedule the show for a ninth season.