LET'S get to the point. How do you impress Samuel L Jackson? You show him you know how to use a blade. "We were in a circus in Blackpool and there were these knives," Finlay Macmillan is telling me on a bright August afternoon in Glasgow. "And I was throwing these knives. Not aggressively. Just flipping them. Pretending I was in a film or something. And Sam said 'aw, nice knife skills, man.'

"I was just like 'wow, Samuel L Jackson has just commented on my knife skills.'"

He looks at me. He can see the question on my face. These knife skills, I say. Where did you pick them up? "Years ago, watching Star Wars." He looks at me, thinks he can see what I'm thinking. "'I'm not in a gang in Glasgow."

Well, that's alright then. I was wondering.

Finlay Macmillan – Fin to his friends – is 20 years old, a good-looking Govan boy who lives with his parents, a one-time Buchanan Street busker and a none-time Weegie gang-banger. Oh and, as of this weekend, he's definitely someone you can see in your local multiplex appearing alongside Samuel L Jackson.

Not just Jackson, in fact, but Eva Green, Judi Dench, Terence Stamp, Rupert Everett and Chris O'Dowd too. It's called Miss Peregrine's Home to Peculiar Children. Macmillan plays one of the latter.

And did I mention it's a Tim Burton movie? No? Well, it's a Tim Burton movie.

For someone who is best known – if he's known at all – for turning up in River City and Waterloo Road, this, as you might imagine, is quite a big deal. Does he feel like he's suddenly on the edge of big things?

"Yeah, the film's coming out so I feel like I'm on the edge in a nervous sense. What way is this going to go? But I like the adrenalin. I'm not an adrenalin junkie, but I like the excitement."

When we meet he hasn't seen the movie yet. "My mates have seen it," he says, meaning his co-stars Asa Butterfield and Ella Purnell. "I'm in it," he confirms. "I'm in it a good bit. And they think I'm OK."

He thinks about it a moment. "But then you would say that. You're not going to phone up somebody and say 'you're shite.'"

In person Fin MacMillan is a gallus mix of puppy dog enthusiasm, honest ambition and wide-eyed surprise at the place he's ended up in. He's up for some jobs he can't talk about yet, he's been to Los Angeles putting out feelers. And all this just three years after making his TV debut in River City.

He first heard about the Tim Burton job when he got a message from his agent to go and meet the casting director. He did, auditioned and then heard nothing for so long he had completely forgotten about it.

"And then a few months later I got a call asking: 'what's your availability next year for a costume fitting?'"

He gave the obvious answer. "'I'm available. I'm very available.'"

"I went down and did the camera tests and met Tim. It sort of just happened before I realised what was happening to be honest. I always felt I was going to be fired or someone would come up and tap me on the shoulder and …" He drops into a stage whisper … "Why are you here? You're not supposed to be here.'"

Maybe that sense of disbelief was inevitable. He grew up revering Tim Burton's movies. Pulp Fiction, starting a certain Mr Jackson, is one of his favourite films. And here he was on the same set, showing off his knife skills to the latter.

What did he talk to Samuel L Jackson about when he had the chance? "I didn't talk to Sam much because I was quite scared of him. He's too cool, you know? I'm not cool enough to go up to him."

As for Burton? "Tim is really eccentric and down with his art. I think Tim inside was a bit giddy that Samuel L Jackson was over there."

Is the director the eccentric he's portrayed as? "I was terrified of meeting Tim because – this is not a lie – if you had asked me when I was 10 years old what movies do you want to be in I would have said 'Tim Burton, Johnny Depp, that crew'.

"So I was terrified of meeting him. I went to his house in London and I mean I was sweating. I went into his office and he's really clumsy, man. He tripped over a table and stubbed his toe. I was just like 'phew, he's taken the edge off. He's a down-to-earth guy.'"

Well, yes, literally by the sound of it. "He is clumsy. He walked into a camera on the shoot. The director running into a camera.

"He's not what you expect," MacMillan adds. "I don't want to say he's not business-like. I just mean he's really welcoming as a guy. He's really nice. He's very playful. There was one day he soaked someone with a water pistol.

"When he's in the zone you see his mind work. He's very fixated on it. You know that isn't the time to go up and soak him with a water pistol."

Did you do that at any point? "No, but I did soak the other kids."

Fin MacMillan grew up in Govan a single child of a Scots-Irish mother and a French father whose own parents were from Madagascar. When her parents separated her mum remarried. His stepdad is in banking, his mum's in property. Possibly, on reflection, being in a gang was never an option.

Growing up, MacMillan lived in his head, acting out the things he watched on telly, all the action movies, the sci-fi movies, the James Bond movies in his back garden. The knife skills come from playing with toy light-sabres "that flicked in and out."

If he didn't have a light sabre a stick would do in its stead.

"I used to jump across the bin dykes at the back. I liked doing parkour. A nice hot day in Govan jumping over walls. My happy place was just running about."

You could argue it still is. Is acting anything more than an extension of childhood playing, Fin?

"Some people say that acting is hiding who you really are and that's why so many actors are nuts," he says. "But I beg to differ. By being the character, by going to work and having fun you're being yourself. You're not being someone else. That's not really possible. You're always in your own mind. What you do as a person is still you.

"So, acting for me is exploring yourself. It's not hiding yourself. You learn new things about yourself, things you never thought you'd be able to do. On Miss Peregrine it was 'Do you want to do your own stunts? Do you want to go underwater?'"

If you're not hiding are you showing off then?

"Hmm, I guess you could say that, yeah. But you're being asked to show off. I mean if you're at a bar and you're not getting paid to show off that's just stupid. But if you're at work. If you show off and you try to make your piece better for the director that's a good thing."

He went to acting clubs as a child and never stopped. His parents sent him to Lourdes Secondary in Cardonald because its drama department had a really good reputation. They were nothing but encouraging.

Friends too? Umm, less so, it seems. "A lot of my mates were like 'Aye, that'll happen. Jog on.' My friends didn't reject it but I got slagged off. It's a bit like saying 'I want to be Brad Pitt one day.' It's not realistic, is it?"

If he's honest music rather than acting was his first love. He plays guitar, used to be in a bluegrass band in his teens playing mandolin. He'd still like to make an album one day.

Maybe he would have pursued that but he just happened to go for a reading for River City for one of his first auditions and he ended up getting the job. He played Mark Walker, a young vulnerable man with a druggy past. (For Waterloo Road his character Dale Jackson was all eating disorder, twocking and impotence. A step up really.)

"I'm really happy my first job was River City because my mum watched it and my granny watched it and everybody knew what it was. And the place it's set, Shieldinch, it's not a real place but it's modelled on Govan, I think. So I feel it sums up who I am in a way … Not that I'm a heroin addict."

By now we're sitting in a taxi. There are pictures to be taken. A dreaded sunny day so we meet the photographer at the cemetery gates. The Necropolis. Fin's never been here before.

But then, he says, he is realising how little he knows of his own country. He's just bought a car and he's loving driving it around.

"I went up to Mallaig a few months ago with some mates. We went to this place called the Silver Sands of Morar and I was absolutely gobsmacked. It was like this tropical white sand beach in the middle of Scotland. 'Why are you here? You're not supposed to be here.'

"You can go anywhere. But the first place you go is the McDonald's drive-thru."

Of course it's possible in future he can live anywhere too. But it doesn't appear to be something he's seriously thinking about.

"I don't know if I'll ever move to London. I was thinking seriously about it during the making of the film but to be honest if there's a meeting that I can't make I put myself on tape. Or if I go to London, I'll just fly down and stay with someone. It's very easy. I don't think I will move to London. I like Glasgow too much.

"I got the bus the other day and there were these two old women gabbing away, these two grannies. And I just thought this is really nice. Everyone's talking to each other and I like that. London's such a major city and everyone moves there for work. They don't have the family with them. They move there single or with their girlfriend or whatever.

"I feel like in London it's all business and I enjoy going down and using that business; power-walking to meetings and stuff. But I love coming home to Glasgow and taking my dog for a walk and seeing who I bump into. That's why I'm going to stay in Glasgow. Not that I won't go and stay in LA for a few months but I'll always live in Scotland."

Ask him about ambition and he talks about doing a movie that's purely about acting and not CGI. He raves about Ken Loach. Then again, he also loves James Bond. "That's got to be the ideal part for any guy. That's got to be. I can't think of a better part for any young British guy."

His heroes are Sean Connery, Johnny Depp and maybe even Jason Statham. Do the recent reports of Depp's alleged domestic abuse put a dampener on his vision of his hero? "I don't really know what's happened. I doubt we're hearing the true story. It doesn't change my idea.

If I ever met Johnny Depp and he said something I didn't like maybe I'd go off him. But I have no reason to dislike him. I don't really read newspapers. I tend to avoid what's being said about actors or musicians because I think you're never hearing the full story."

This is possibly not the place to have a debate about media ethics. And anyway we don't have time. He's ready for his close-up. He has a career to kick-start.

What if things go wrong for him? Does he worry about failure? "I've never thought failing's a bad thing. When you haven't failed you haven't tried. You need to fail in order to learn."

Fin MacMillan is ready to fail if that's what's required. But if any director also needs an actor with Samuel L Jackson-approved knife skills, look no further.

Miss Peregrine's Home for Peculiar Children goes on general release on Friday.