The cast of 'Trainspotting' were ''nervous'' about making a sequel.

Danny Boyle directed the original movie in 1996 and has returned for the much-discussed sequel - but he's revealed the cast of the film were uncertain about whether to reprise their roles.

The director - who's once again working with Ewan McGregor, Jonny Lee Miller, Robert Carlyle, and Ewen Bremner on the new movie - said: ''The actors were very fearful about a sequel as well!

''Actors are a great barometer of whether something is worthwhile or not. Their bulls**t filter is very, very strong, because they're going to be the ones out there trying to make a script look truthful and believable.

''When it comes to doing another 'Trainspotting', they were very nervous, because for all of them, it's a large part of their reputation and they feel very protective towards their character.''

Meanwhile, Danny also promised the sequel will do justice to the original movie.

Reflecting on the script of the new movie, Danny told Vulture: ''It had this feeling about it, where it honours the original and it won't disappoint people.

''It's not the same film, but it can't be, and we wouldn't want it to be. And the actors all responded to it as I thought they would.''