BILL Murray doesn’t so much break down expectations, as blow them into tiny pieces. The result, according to the actress Naomi Watts, is, “Wherever he goes, he’s leaving a trail of hysteria behind him.”

The actor is prone to random acts – of kindness, madness and

minor mayhem.

Take a few examples; the actor who rose to fame with Ghostbusters in 1984 has been known to crash strangers’ karaoke parties, give a boy $5 to ride his bike into a swimming pool and steal a golf cart and drive it into to a Stockholm nightclub.

To add to the endless list of eccentricities, he’s read poetry to construction workers, refuses to book round-trip tickets – he buys one-ways and then decides when he wants to go home.

And if a producer wants him to appear in a movie, well, Murray doesn’t have an agent, or a mobile phone, so the hopeful has to find a friend of the actor who will pass on the message, then sit back and wait.

After he agrees to be in your movie, you may not hear from him again until the first day of shooting, when he’ll “show up in the make-up trailer, cracking jokes and giving back rubs.”

Now, Murray, married and divorced twice, has again caused the world to raise a curious smile with his latest project.

Bill Murray, Jan Vogler & Friends is a music ensemble billed as New Worlds. Playing theatres and concert halls across the world, Murray and chums (with Vogler on cello) perform a range of musical offerings, by composers such as Bach and Ravel.

Murray also carries out readings from the likes of Hemingway, Whitman and Twain. And he sings. Sort of. Songs include Jeanie with the Light Brown Hair and a West Side Story medley of Somewhere, I Feel Pretty and America.

The fact the songs are very difficult to sing suggests he’s bonkers to even try. But the one-time Groundhog Day star says the whole idea wasn’t thought out. It sort of evolved.

“When Jan said we could do a tour and travel the world, I thought ‘That’s a fun idea.’ But I didn’t imagine it becoming a theatrical event. I saw it as something you would see on public television in the middle of the night.”

Murray and German-born musician Vogler met on a flight from Berlin to New York. They struck up a friendship, “mingled in each other’s creative circles” and began developing the idea for their project. “Now, we are playing the most beautiful houses in the world. We are playing incredible concert halls. It’s kinda like a church tour in the sense we’re bringing sacred music into these temples.”

Murray admits he confounds expectation with this tour – comedy icon turns crooner. Was he fearful of the challenge?

“It’s no different from the fear I feel when people see me in everyday life,” he deadpans.

“They sort of look at me and say, ‘Oh, my God, is that what you look like in person? And you’re taller than I thought.’”

He breaks into a laugh; “I usually say ‘If you’re watching me on TV then I’m only 27 inches tall’.”

Murray grew up in the suburbs of Chicago, the fifth of nine children. His father, a lumber salesman, died when Bill was 17. He spent his 20th birthday in jail, for possession of marijuana, and after probation, pursued acting.

Six years later, he broke through on of Saturday Night Live, and since then his desert-dry delivery has defined him.

But could he have seen himself vary his performance so much in this new format show, with singing, narrating and acting? “Well, in this strange world we actually recorded an album before we toured. Who the heck does that? And in making the record I wasn’t at all sure people would want to hear my singing voice. And some [songs] aren’t easy at all. With the high notes I decided to speak them although now I try to sing a bit more.”

He adds: “Yet, the lyrics are poetry. The words have a power and sometimes the melody actually gets in the way. And this is storytelling. That’s what it’s about. Audiences already have the melody in their bodies already.”

There’s an honesty in his self-appraisal. “I have great musicians with me, and my singing isn’t going to help the melody. My job is to tell the story.”

Ted Melfi, the director of St Vincent, Murray’s 2014 film about a former Vietnam vet who turns reluctant babysitter, once offered the quote: “Bill’s whole life is in the moment.”

He seems to have called it right. A few years back, Murray caught a cab late at night in Oakland, began talking with his cabbie and discovered his driver was a frustrated saxophone player. The actor told the driver to pull over and get his horn out of the trunk; the cabbie could play it in the back seat while Murray drove.

Right now, Murray, often reclusive, sometimes both voluble and volatile, is seriously committed to a European tour. Does this commitment conflict with his need to live in the moment? Or does he see the tour as a very large collection of moments? “You’re right. It’s a very large collection of moments and there’s a daunting responsibility to get it all right. You have to show up and bring as much as you can every night.”

The 67-year-old admits the commitment takes its toll. “An hour before the show I can find myself thinking ‘I can’t possibly do this. I just don’t have the strength. But then something wakes up inside of you and you come out of the dark shadows into the light. You have to deliver the goods.”

Despite the rigid self-examination, Murray sounds as though he’s in love with the show concept. He’s had a month off performing and he says he’s been singing the songs from the show during that time. “I want to work on the material and see what we’re doing with it. I really want to go to Orkney or Athens and see what happens.”

Does the project have an added appeal in that he’s conquered the mountain that is comedy film? “You always feel you are here [on earth] for some reason, rather than breakfast or lunch. And perhaps this material is really demanding.

“But I work as best as I can all the time, whether I’m doing a voice on a cartoon movie or Shakespeare.

“And by performing this array of composers and writers, I have to offer a wide range. The intensity level is the same but I have to come up with more colours in the course of the night.”

The chat wanders to more general subjects, such as his perception of Scotland. “My ancestors are more Irish so I wasn’t sure what to expect, and I’d heard this rumour of the Scots being penny- pinchers. But rather, I found them to be thrifty. Once I was in a bakery in the north of Scotland and I opened up a box of pastries and the shopkeeper asked ‘Are you not going to keep the string?’ And I agreed. It made total sense. I’m a natural hoarder.

“But I also discovered the Scots were a lot funnier than I had imagined. They cracked me up. I loved the darkness of the comedy.”

Did he connect with Billy Connolly’s sense of humour. “I’ve connected with Billy’s darkness on a couple of occasions,” he says, laughing hard then adding: “I used to see Billy every couple of months, but that’s because I don’t live in New York so much now and he’s always on the move. That takes you out of the circuit of seeing your professional friends. But he’s great. A real storyteller.”

Is it a good time to be out of America at the moment? “Well, we’ve just done around 20 shows in America, driving between the cities. But you know, if you’re not watching CNN, America is a different country. There are real people out there, real life. And these are the people we bump into it all day long.”

He adds; “I think our shows represent what’s best about America. We’re a really mixed band.”

Does President Trump frighten him? “I grew up thinking politics was about agreement, negotiation, but nowadays it doesn’t happen. It’s about trying to thwart an opponent. It’s about getting re-elected. It’s an ugly time in that regard and I haven’t seen anything like in in my lifetime. And it’s drowning out the ordinary voice of America.”

The songs and pieces he performs with Vogler and Co are connecting with audiences, he says, because they represent the feelgood factor.

Murray worships a stress-free life. He loves to treat the universe as his private playground and to find a way to inject fun into mundane moments.

And he wants to bring something of this intent to the performances. “We didn’t set out to create a show that’s balm for the pain but that’s what seems to have happened. People do feel good afterwards. It’s a validation of what people feel in their heart. It’s a joyous hit.”

Could the project run? “I think so. Every time we go on stage we come up with something new. As a result, we go out there and think, ‘We’re gonna kill ‘em.’”

He laughs hard and long. “What’s great is there’s a different sort of murder every night.”

Bill Murray, Jan Vogler &Friends: New Worlds UK Tour. The Festival Theatre, Edinburgh, June 18.