Danny Boyle has revealed that a Trainspotting sequel will move forward once the original cast begin to look older.
The director explained that the storyline will take place two decades after the events of Trainspotting, when the characters "hit the wall" in middle age.
However, Boyle said that Hollywood vanity is slowing down the ageing process for stars Ewan McGregor, Robert Carlyle, Jonny Lee Miller, Ewen Bremner and Kevin McKidd.
He told The AV Club: "The problem is, they don't look any different at the moment from when Trainspotting was made. They look exactly the same. They're a little heavier, but they basically look the same.
"Actors stay suspended in that timeless moment where they're moisturising and looking after themselves and making sure they keep fit and healthy, because it's their work, it's their future employment. But when time ravages them, we will be waiting for them."
Trainspotting author Irvine Welsh wrote a sequel to the novel called Porno, which follows the same characters working in the pornography industry.