It seems like the development of the sequel for Trainspotting is on a roll, as after confirming that the movie is on, Danny Boyle recently confirmed some other promising details.

The movie is bringing back the original pack Ewan McGregor, Jonny Lee Miller, Robert Carlyle and Ewen Bremmer -- even though some of the cast members had expressed concerns at first. In an interview with Vulture Boyle revealed how things were a bit sticky at first.

"The actors were very fearful about a sequel as well!" Boyle said. "Actors are a great barometer of whether something is worthwhile or not. Their bullshit 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." 

Boyle also spoke about the film in a previous interview with The Hollywood Reporter while promoting his latest film, Steve Jobs. The director revealed that prinicipal photography for the sequel is expected to begin in May or June next year. The schedule has been worked out keeping in mind the other commitments of the core members of the original cast, who are set to return. Boyle did add that to make this happen they might have to work with a very tight schedule and wrap filming quickly.

"They only get this little window off, so either you wait for the contract to run down, which could be as late as three years, or you kind of try and do it in this window," he said. "But all four lads are back in."

The director also spoke about the budget of the film and how it will in someway similar to how the orginal was made (in just $2million).

"We're doing it for less than $20 million, and that'll give us control of the film so we can make the film we want to make," he said. "That's as much as you can get without being answerable to anybody. You can sort of get on with it without much interference. Although we could have raised a lot more money for this, we didn't, so we're trying to keep some sense like we kept the original."