'How many times do we have to be slapped in the face by Westminster?'

“I was appalled when I heard the result. And I have three words to sum it up. Stupid. English. People. But you could see it coming. I did an interview for STV news a couple of years ago and I said there would be a referendum on the EU and Britain would vote to leave, but Scotland would want to stay.

“I also said we’d have another (independence) referendum. Now, I hope that people will see the irony in that one of the major reasons the Yes vote didn’t win was people were scared we wouldn’t be allowed in the EU if we were independent. And now we’re not allowed to be in the EU because we’re part of Britain.”

The actor’s voice turns contemptuous as he asks rhetorically; “How many times do we have to be slapped in the face by Westminster?”

Cumming may have left Scotland for London in the late Eighties and nowadays he’s a New York-based American citizen (he signed up with Uncle Sam to be able to vote for Obama). However, it seems the 51-year-old from Aberfeldy will not surrender his Scottishness any time soon.

“What is interesting here is people like you because you are Scottish,” he says of American life. “They like the way you sound, what you have to say. When I first came to New York I realised a lot of things I was being lauded for was the kind of things I was being put down for in London, which is essentially being Scottish. The Americans just don’t talk about your Scottishness in a derogatory way as they do in London. And I love this. I love the fact I’m a product of the Scottish education system. I feel I represent Scotland in a way.”

Cumming’s upcoming Edinburgh Festival cabaret show, Alan Cumming Sings Snappy Songs, will see him perform the likes of Keane’s Somewhere Only We Go and Miley Cyrus’s The Climb. But in a Scottish accent.

Is the choice of singing style a deliberate, or perhaps an unconscious paean to his nationalism? “It was totally deliberate,” he says, in emphatic voice. “I’ve always felt it weird that when we sing pop songs we immediately use an American accent. Everybody in Britain does. But it doesn’t really make sense. Take someone likes Adele, for example, who speaks amazingly and she’s such a giggly Cockney girl. Yet, when she sings she becomes this different person. It’s like she’s acting this fake R&B diva. I always find it fascinating why people do this.”

His voice changes tone and he gushes; “I guess this is why love the Proclaimers. I’m so full of admiration for them and the fact their passion and their Scottishness is way up there. So when I decided to do this show there was a lot of things swirling around in my head, but one of the things was if I was going to sing I wanted to sing as me.”

Cumming took some time to discover who ‘me’ was. “When I appeared in Taggart (in 1986 as a suspect) I remember finding it really hard to play a young Scottish boy because I’d just come out of drama school and had never really played any character in my own voice. (It was the days before regional accents were deemed acceptable). It made me very conscious how important it is to hang onto a sense of self.”

In Edinburgh he won’t have a character to hang on to. And this is real singing, not Victor and Barry singing, (his Eighties duo with Forbes Masson featuring two satirical and very fey thespians). Will he feel vulnerable? “Oh, yes,” he admits. “You’re not playing a character, so people are coming to see you. And what you’re doing is saying ‘I’m a singer’. I’m not that comfortable with that.

“Yet, you have to do things that challenge you and scare you. I do think the best work I’ve done is where I’ve pushed it. What makes this show work I think, is that I’m prepared to be vulnerable.”

He pauses for a second; “I've been getting it (acting) all wrong, thinking it's all about putting things on top of yourself and hiding yourself. But instead it's about letting yourself come through. When I realised this it was a big revelation.”

Was there a sense that going back to the essence of performance – one man and a microphone – with only one character on stage, his own, was the only way to go at the moment?

“I don’t really think that way,” he maintains. “I’ve never thought that way. I can see why people assume an obvious career trajectory plan, but the truth is I’ve always done what I wanted to do. I do what I enjoy and right now it makes me happy to be connecting with an audience in a way I haven’t done for years.”

Cumming has certainly rung the bell, in terms of dollar associations, with the likes of the X-Men films and his two Smurf movies. But over the years, he has also wowed a very different audience with raw, visceral stage work, such as his 2012 Macbeth, which saw the Scottish king’s story played out in an asylum, or The Bacchae in 2009, in which he wore a gold skirt and a delicious sneer on his face.

“I’ve just done a couple of movies, I’ve just finished a TV series, I just wondered what I would do next,” he says of his cabaret show. “But I would say it’s not always about doing big movies next. Some of the blockbusters I’ve done I’ve absolutely hated them. I’ve had my worst time ever.”

He’s not lying. When he filled out his American citizen forms Cumming tackled the expected dull questions; ‘Have you ever killed anyone?’, that sort of thing. But when it came to the more surprising ‘Have you ever been a prostitute?’ the actor grinned and wrote; ‘Not really. But I’ve been in some films that have made me feel like one.’

“Some of the more obscure things that most people have never seen have given me the best time of my life. What I’ve learned is that it’s the experience of doing it that counts, not the end product. I really follow my gut.”

The young Alan Cumming took a little time to discover the true direction of his gastrointestinal tract. On leaving school he joined publisher DC Thomson in Dundee to work on Tops magazine where he interviewed bands and edited comic strips. It was fun, but he had known for some time he wanted to be on the other side of the showbiz fence and was accepted by Glasgow’s RSAMD.

It was at drama college he met Forbes Masson, the pair became chums and Victor and Barry was born, the comedy duo that became a Fringe hit that lasted 10 years. Along the way, Cumming appeared in STV soap Take The High Road as a murdering psychopath and Taggart, as a suspect. He joined rep theatre, and he starred in sitcom The High Life, playing a camp flight attendant. But he never became typecast and set out his stall in dramatic theatre with the Traverse Theatre’s production of Conquest Of The South Pole, which transferred to London’s Royal Court and saw him Olivier nominated.

A major film career was almost an inevitability and Cumming was delightfully oleaginous in the 1995 Minnie Driver movie Circle Of Friends and thoroughly geeky as the Russian computer fiend in Goldeneye in the same year. His rampant eclecticism saw him become a transvestite in Sky series Runaway, a rent boy in Rent, and he’s starred in such films as Stanley Kubrick’s Eyes Wide Shut and The Flintstones In Las Vegas. Along the way, not surprisingly, he has won an Olivier and a Tony in the West End and Broadway.

Yet, for so long his performance, he admits, was contained, no doubt a result of repressed emotion. His seriously disturbed father physically battered him (and his brother) over the years, cutting him off from friends, crushing Cumming’s emotional development. The nervous breakdown he later endured was almost inevitable.

Two years ago he wrote his very successful autobiography I’m Not My Father’s Son, in which he revealed how his dad virtually tortured him and his older brother.

“I talk about the book and my father in this new show,” says Cumming of the evening which is a mix of song and chat. “I think it’s because the responses to it were so gratifying. That was the thing that was most shocking to me, in a very positive way. Going into the book opened up myriad feelings of anxiety for me and I wondered if I had made a mistake. I was very, very worried.

“But it’s given others the courage to talk about their own problems with family. I hadn’t bargained on it helping so many people. And for my mum and brother it’s been great because they’ve had such incredible support and validation.” His soft voice betrays his emotion; “It’s one of the things I’ve done I’m most proud of.”

The idea for Sappy Songs came about after coming off stage from his Cabaret run in New York and his "infamous dressing room parties", in which Cumming would entertain friends.

Time Magazine once labelled the Scot "one of the three most fun people in showbiz", which says a great deal for the man who managed to bury the past and live in the moment.

On a personal front, he’s now married to his long-term partner, Grant Shaffer. But what of the future? Does he plan to come back to Scotland? His New York apartment went on the market recently (It’s yours for $2.2m if you’re thinking of a move).

“I put the house on the market because I bought another one around the corner,” he says, smiling. “But I have a flat in Edinburgh.” He muses; “I don’t know. I like living in New York but I like being able to come back.”

Work (and Alan Cumming) will continue to be delightfully unpredictable. “I love what I’m doing. I’m eclectic and I get offered such a range of nutty things to do and sometimes I say yes. I’ve also got a new book coming out, You Gotta Get Bigger Dreams: My Life in Stories and Pictures, in September. I feel connected. And I’m one of these people who, if it's not working I change it.”

Cumming can see a change too in Scotland: “Independence is an inevitability,” he maintains. “As someone who goes back and forward a lot, I see a great expansion in Scottish confidence. And I hope we will all come together in the end.”

He adds: “I do know we couldn’t be in better hands.”

Does he ever look back and wonder if he had stayed in Scotland? The hinges on the doors of opportunity weren’t so well oiled back then, certainly not in the Eighties when he left drama school.

“That’s true. But I got lucky. I got a play at the Traverse and the Royal Court. And I had Victor and Barry. And I went to London with something to show. It was the same by the time I went to LA, and onto New York.”

He adds, grinning as he speeds off in the direction of the beach. “I’ve been very luck with all these entrées I’ve had. But at the same time I’ve given it a right good go.”

Cumming breaks into a loud laugh and Victor and Barry voice. “And right now, I’m in my prime!”

Alan Cumming Sings Sappy Songs, The Hub, August 6-27.