24 star Kiefer Sutherland has revealed that he had serious doubts about signing up for the TV series when he was first asked.

He recalled: “I was sceptical about doing a television series, and Steven Hopkins, who directed the first year of 24, was a very old and dear friend of mine.”

“He was persistent and said, ‘Come on, it’s going to be, we are going to make something, it will be very cool.’

And he convinced me that we might have a shot at doing something that people, that we would like, and that we would be proud of.”

He added:

“When you sign on to a TV show, you’re looking at one script. We have made 175 of them and there is no guarantee that the 174 coming are going to be any good, I had every reason to be sceptical,” he explained.

“It’s also, I think, we fear what we don’t know. The idea of playing the same character for six years, I would have thought that would have been boring – and how arrogant of me to think that!”

But there are no regrets for Sutherland:

He said: “Now that I am looking back, it’s actually been one of the most exciting acting challenges of my career.”

24 Day 7 starts on Monday January 12 on Sky1 and Sky1 HD.