Stillness is a great quality in an actor, and a rare one. David Hyde Pierce is pretty much still most of the time.
We are sitting in his underground dressing room at the Comedy Theatre, where he has just opened, to very favourable reviews, alongside Mark Rylance and Joanna Lumley in La Bête, a rhyming play about 17th-century French actors.
I say that I won't even mention Frasier. He neither twitches nor smiles. Then, of course, I do mention Frasier. Same reaction. He's placed his early lunchtime tuna baguette to one side – there's a matinée in two hours' time – and offered me a glass of apple juice. He's concentrated, watchful, Buddha-like, even though he's wearing sportswear and trainers. His crash-pad day bed is tidily arranged in the corner.
I realise now that those slow burns and sudden eruptions of mania as Dr Niles Crane in television's most popular ever sitcom – it ran for 11 years between 1993 and 2004 – are rooted in a steadily controlled lifestyle and demeanour. If Hyde Pierce has high blood pressure, I'm a Dutchman.
There's not much small talk, not with journalists, anyway. He was born and raised in Saratoga Springs in upstate New York, and went to Yale to study music, switching to a double masters in English and theatre studies. As a student he played in Beckett and Gilbert and Sullivan, and made his Broadway debut, auspiciously enough, in Beyond Therapy by Christopher Durang in 1982.
Was it true that the role of Niles Crane, Frasier's younger brother, was created for him because he looked like Kelsey Grammer? "In a word, yes. The casting director said to the writers that if Frasier were to have a younger brother... and so they came up with me and the construct of two brothers, two therapists with different kinds of therapy and different educational backgrounds. And that was that."
Wasn't it a grind, year in, year out? "Not at all. With a live audience very week, and those scripts, it was always perfect for me. And there is always time off; I'd have four months out and do a movie or a play. One of the great experiences of my life was doing a two-hander, Six Dance Lessons in Six Weeks, onstage with Uta Hagen; it was the last thing she ever did, and there was something magical in our partnership. I learned so much from her, just being with her on stage."
Talking of legends, Hyde Pierce also worked, pre-Frasier, with Peter Brook, playing the house servant Yasha in a specially re-vamped US version of Brook's Bouffes du Nord Cherry Orchard, alongside Brian Dennehy, Linda Hunt and the great Ingmar Bergman actor, Erland Josephson. So his renewed stage career is a happy return, not a tentative new start.
We all know he is, as the New York Times put it in 2000, "a comic-pathetic actor of genius, a sort of modern day Buster Keaton for TV." So had he read the reviews, which have been mixed, of La Bête? He gives me a look which says, "Why would I have done that?"
The trouble with his role, that of Elomire (or Molière the playwright), is that he has to stand and listen to Rylance as the upstart thespian Valère spouting brilliantly through false teeth for half an hour. I was going to ask if he felt that acting was as much about listening as speaking, but the question sticks in my throat, already unworthy of his consideration.
"When my sister read it," he offers – at just turned 51, he's the youngest of four in a close family, many of them recently over for the première – "she said, what do you do all that time?" One critic has suggested that he's slowly realising that he's playing the wrong part. I'm not even going there... "In a way, we are the audience on the stage. Everyone knows someone in their life, hopefully not as extreme as Valère, who prattles on so you can't actually believe they're still talking."
So why had he taken the sponge-like role of Elomire? "The project came to me, although the writer, David Hirson, reminded me – I had completely forgotten – that I'd auditioned for the role of the Prince [it's now a princess, played by Lumley] in the first production in 1991. And not got it. It was near the end of my time in New York, before I went out to LA for Frasier, and they hired a fine actor called Dylan Baker. I'm told I was very close.
"I never saw the show, but it's remembered for two reviews: Frank Rich's in The New York Times, which killed it; and John Simon's in New York Magazine, equally dismissive, which was written in rhyming couplets. When I re-read the play, I wasn't interested in the Prince, but Elomire fascinated me. Our director, Matthew Warchus, knew there was a dark side to the play, and we discovered that; it was always going to be worth the journey."
But is the piece really any more than an over-contrived conflict between the meretricious and the serious in theatre? "Matthew describes it as a conflict between idealism and reality, and each of us has our better self and our practical self, and every day is a process of juggling those claims on us. And there's also what it means to be an insider and be cast out, which is what happens to Elomire. He's an insider in a world Valère wants to gatecrash, and it may be poisoning him... "
When he first left Frasier, Hyde Pierce bounced on to the Broadway stage in the Monty Python musical Spamalot, playing Sir Robin ("not quite so brave as Sir Launcelot") and leading a flat-out funny ensemble number about the need for Jews in all Broadway shows: "There's a very small percentile who enjoy a dancing Gentile." I saw the show on its first weekend, with queues of obese Mid-Westerners, savvy New Yorkers, musical theatre buffs and geeky Python fans snaking right round the block and down to Times Square.
"I'd been waiting for this for many years, and had been in training, and singing in benefits. I knew that once Frasier finished, musical theatre was the next thing for me. I wasn't obsessed with Monty Python but, when I was a kid, after I'd finished my organ practice one night in the church, the show came on a local PBS channel; it was the sketch about the tedious life of a chartered accountant, not even one of their best sketches, but it was bored into my brain from that moment."
The fact that the Spamalot director was Mike Nichols hit another button: Hyde Pierce was a devotee of the deadpan cabaret sketches Nichols recorded with his comedy partner (and then wife) Elaine May. "Mike and Elaine's work was a huge influence, so was Bob Newhart's... and Alec Guinness. They all made a big impression, but there was also something in me drawn to their sardonic style of humour. But I enjoy slapstick, too. In Frasier we had the chance to do both."
I think of Niles with a parakeet on his head at a dinner party, or setting his pants on fire, or pretending that a sack of flour is his baby, or trailing around after Daphne Moon like a spaniel with indigestion. Are the Frasier gang still close? "Totally. We went through a lot together, in our personal lives as well. I've just been to see Kelsey in La Cage aux Folles on Broadway, and I came to London for Jane Leeves's wedding."
Ah, so there might be a stage version, perhaps even "Frasier: the Musical"? Another blank look. "No, we don't want to do anything like that. It's something we're all very proud of and are happy to leave in syndication. Life goes on." And he loves London. Is he bugged when he goes round the shops? "No. People are friendly when they recognise me. It's a great gift to be able to pretend to live here for four months. It feels like home."
He's been to Evensong in St Paul's and the National Gallery and is planning to catch as many concerts as possible. His last Broadway show, for which he won a Tony award, was a "theatrical" musical, Curtains, by John Kander and Fred Ebb, and he went the other night to see a Guildhall School production of it. "It was very moving. I cried, seeing this show we had created done by these amazing kids, with a really fine orchestra."
His partner, TV writer and producer Brian Hargrove, has just returned to New York, where La Bête follows in September. I wish him and the play better luck this time round with The New York Times. He doesn't respond, but shows me with an almost eerie politeness to the stage door. And he shuffles quietly back towards his bunker and his baguette.
'La Bête', Comedy Theatre, London SW1 (0844 871 7622; Labetetheplay.com) to 4 September