Ewan McGregor and Jonny Lee Miller are not happy about being older

Do you remember seeing “Trainspotting” when it came out in 1996? Then guess what? You are officially old.

That’s OK, because the cast of “T2 Trainspotting,” its new, belated sequel, aren’t handling that well either. Ewan McGregor and Jonny Lee Miller reprise their roles as Mark Renton and Sick Boy, now going by the more respectable “Simon.” Both have cleaned up, got off heroin, but that doesn’t mean they’ve figured life out. When Renton returns to Edinburgh, Scotland after 20 years away, he finds that Simon is still a hustler, Ewen Brenner’s Spud is still on smack and Robert Carlyle’s Begbie, in prison since the first, and thanks to Renton, has escaped and wants vengeance.

We talked to McGregor and Miller — now 45 and 44, respectively, horrifyingly enough — about getting the band back together and how aging sucks.

RELATED: Review: “T2 Trainspotting” will make you feel horribly old

I saw the original “Trainspotting” when it came out, and I’m horrified to find out 20 years have passed. How did you two handle that?

Ewan McGregor: It was very much a daily part of the experience of making the film. Every day there was a “20 years ago” moment, where you were faced with the passage of time — never moreso than when we bumped into the people who had been cast to play us at that age. [Laughs] There were five guys who had been cast in flashback scenes because they looked like us, and they were wearing our old costumes. Whenever we bumped into them it was always a bit of a shocker.

Jonny Lee Miller: An even more shocking happened at the premiere party in Edinburgh. We met these twins, these cute 20-something girls — who turned out to be the baby [from the original]. When you use a baby, you usually use twins so one’s not there for too long. We were talking to them and they said, “We’re the baby.” [Laughs] That was f—ing brutal.

It doesn’t seem like it’s one of those ’90s staples that have been forgotten. The kids these days seem to know it, too.

McGregor: My eldest daughter’s 21, and her friends have a relationship with the original film. It’s really lasted. It stood the test of time.

This would make a good double feature with the doc“Oasis: Supersonic,”another time capsule about things that are way, way too far in the past.

McGregor:That’s a really good one. I love that documentary. It had a similar effect on me that this film does. It takes you back there, it makes you nostalgic for that time. There’s something Noel [Gallagher] talks about in the film: that Knebworth [Oasis’ biggest concert] was pre-Internet. That can never really be repeated. You can’t go back to that way of life where there was no Internet, and 250,000 turned up at the concert because they wanted to be there. It wasn’t an Instagram thing.

At the same time both “T2” and “Supersonic” are about people reflecting on their past, which can’t be reclaimed.

Miller: The point of the movie is you can’t be that again. Your time is done. You had that moment, but the moment’s there for another group of people. I think it was important that we weren’t trying to recapture [the original] or redo it. We couldn’t have a zany caper again. There’s no point in doing that, because your time is done.

It’s really difficult when you age, but you have to find some way to make peace with the fact that you can never be that energetic again, that your body’s going to decay.

McGregor: Well, not yet. [Laughs] I think you could have ended that sentence with “It’s difficult when you age,” full stop.

Admittedly that felt really insincere to say.

McGregor: But it’s quite interesting: I’ve heard Danny [Boyle, director] talk about how it really centers on male aging, and how badly we do it. There’s this myth that women age worse than men, but they’re actually quite better at it than we are. We hold onto the notion that we’re not getting older, that we’re still cool and young, for far too long. We just cling onto it for grim death.

I interviewed Robert Carlyle once, and it was slightly surreal to discover he’s a very, very nice guy.

McGregor: Depends if you say the wrong thing. [Laughs] I wouldn’t feel too safe in that one.