At the height of Laurel and Hardy's success in the 1930s and 40s, they were the biggest comedy double act in the world.

By the 1950s their golden era had passed, and the new movie Stan and Ollie focuses on their relationship while they're on a twilight tour of British and Irish music halls.

Halla Mohieddeen sat down with the film's Scottish director Jon S. Baird at Glasgow's Panopticon theatre - the venue where Stan Laurel made his stage debut at 16.

HALLA: Did you ever think that one day you'd be making a film about the man who started his career on this very stage?

JON: I never really. I'd been a fan of Laurel and Hardy since I was a kid. There's a picture of me dressed as Stan Laurel at the school fancy dress party when I was eight. I used to watch them every day after school and they were just really heroes of mine. And this is where Stan, as you say, did his first ever performance. It's great.

The film isn't an out and out comedy, it's got comedic moments, but it's very much a love story.

A love story between two friends who are coming towards the end of their careers, their star has faded, they're in ill health and they've got some money issues.

And a lot of drama comes out of that from conflict and challenges they face. But it's obviously still about Laurel and Hardy as well so we still had to inject humour into it.

There is a balance between it. But what happened to them was quite a tragic tale, but through tragedy you do have comedy.

There's a fine balance in the film.

HALLA: The variety hall tour, this isn't a very well known part of the duo's history, is it? Why did you want to focus on this part of their story?

JON: We didn't concentrate on the early part of their career because they were really successful then. So where's the drama in that, where's the sort of narrative?

We found out they had done these tours through necessity really, because they didn't have money left at the end of their careers. They were working for a wage at the studio and didn't look after their money particularly well.

We thought we'd pick the end of their career because they were facing more challenges and therefore with that inherently comes more drama. It's an unknown part of their lives.

HALLA: They're comedic geniuses. They're what many comedians draw their inspiration from. How hard was it to cast the role of Laurel and Hardy?

JON: Steve Coogan and John C Reilly were our first choices. We looked at everybody and said "Right, we need two physical comedians but we also need two actors who can handle the dramatic role as well." And who had the gravitas to handle the big dramatic moments as well as replicate the comedic moments. So we went to Steve and John. John said to me at one point, it's a frightening prospect taking on this role of Hardy, but it's even more frightening to watch someone else do it instead of me.

HALLA: The other double act in the film is of course the wives of Laurel and Hardy. What were you wanting them to bring?

JON: Not really to add the comedy, it turned out that they do sometimes steal the scenes and get the biggest laughs. A lot of that wasn't in the original script, a lot of that came through rehearsals.

HALLA: The actress who played Oliver Hardy's wife was the Scot Shirley Henderson, was she something of a tough sell to producers and casting directors?

JON: John Reilly asked: "Who's playing my wife? Do you know Shirley Henderson?

She should be playing my wife; she is one of the best actors I've ever worked with."

HALLA: It's quite interesting with the film as well to watch things go full circle. They played out through the movies and ended up back on the stage of the music halls themselves.

JON: Absolutely, is it poetic or is it tragic or a bit of both? The thing they realised that mattered was that they loved each other and their friendship endured. So whether by design or by fault them ending up on stage again, I suppose there is poetry to it.

- This interview has been condensed.