Kiefer has taken a house in Mayfair for the duration of filming and in what little spare time he has he has been exploring the Shepherds Market area.
"Have you tried The Grapes pub?" I asked him, naming the Greene King pub tucked away in the corner of the Market. "Yes, it's a great pub," he answered, to my surprise. "I love the chicken pie they do. Maybe I'll see you there."
There wasn't much chance of that as I was only in London for a couple of days to write a piece on the new 24 series which is being filmed under security so tight that the producers aren't giving away any details of the plot and don't even want the location of the studio to be named.
Kiefer, however, was more forthcoming and told me that his Jack Bauer character is on the run in London, pursued by the CIA, MI5 and MI6 while trying to stop a terrorist plot which could change the world.
The story features a Julian Assange-type character who operates a hacking ring from a disused shopping mall and who has as one of his followers Jack Bauer's former sidekick Chloe O'Brian, played by Mary Lynn Rajskub.
Since they have been in London Kiefer and Mary have not only battled bad guys but have struggled to combat the cold and damp of an English winter.
“It’s really different but it’s fun to be here and on the streets,” Mary told me. “It’s colder, there’s a lot of tea and the crew is pretty hardcore. It will suddenly become frigidly cold and start raining and nobody even blinks an eye. They just pull up their jackets, pull some trash bags over the camera and we don’t miss a beat.”