THROUGH the hotel lobby, up the richly carpeted stairs, turn right into the sitting room and there - I can hardly believe it myself - is Patrick Duffy.

Say it one more time: Mr Patrick Duffy has entered the building. The very same P. D. who once starred as a web-toed superhero in The Man From Atlantis, thwarting the forces of evil, while - just like a naughty puppy - permanently in a puddle.

As if this wasn't enough, he then gilded his claim to the hall of television fame by appearing as Bobby Ewing in Dallas, the series that heralded and defined the 1980s.

For 11 glorious years, Duffy's Bobby mooched around Southfork Ranch with a pained expression, his fussy blow-dry rock solid in the Texan winds. Indeed, so potent is the Dallas heritage, that all morning I have been repeating Duffy-Duffy-Duffy's name like a mantra, in case I idiotically call the 51-year-old actor "Bobby".

"Hello, Patrick," I screech when we are introduced, although he is not really listening. Right now, Duffy is having a déjà vu moment. "Have I stayed here before?" he asks one of the hotel staff, supremely confident that she would have remembered if he had.

"Um. Possibly," she replies.

"Do you have a penthouse suite here? On two floors? With a balcony front and back?" he wonders. The answer is affirmative.

"Then I did stay," he says, pleased, ordering tea and strolling around the room.

In a wool polo shirt and beige trousers, he looks screamingly wealthy in that casual, American way and is surprisingly tall - is it me or didn't Bobby always seem like a shrimp?

His hair, attractively greying at the temples, is fabulously cut and his complexion is as smooth as buffed calfskin. His watch, a present from his wife, clunks expensively on his left wrist and on his right he wears a medical alert bracelet to draw attention to his potentially fatal penicillin allergy.

All in all, he really could be the Ultimate Penthouse Guy were it not for his footwear. Readers, there is no easy way to break this news: Patrick Duffy is wearing a pair of clogs.

"I have terrible feet," he says. "I really beat them up during Man From Atlantis because I was barefoot all the time. Running through fields, running on cement, jumping out of the water, slapping 'em around for years. So the nerves on the bottom kinda went all to hell."

He developed something called Morton's Neuroma and had to have an operation in 1989 - not to have the webs surgically removed, but to cut out his swollen nerve endings.

"Since then, I have chosen to wear clogs," he drawls.

Duffy is currently clippy-clopping across London preparing for his role in Yasmina Reza's award-winning play Art, which has run in the West End since 1996 and cornered the market in quirky casting. He is particularly delighted to be here, as he was almost selected for the play a year ago but did not make the final cut.

"It's not my first day at the picnic here. I have been talked about and denied enough times in a 25-year career to know, ah well, that is the way it goes," he sighs, then instantly contradicts himself.

"But you always take it a bit personally. It's like asking a girl to the high school prom. If she says no, and even if you end up taking another terrific girl, you still wonder why the first one refused you."

Although amenable enough, Duffy is distant and unconnected, like a preacher forced, yet again, to address his recalcitrant flock. Perhaps much of this chilly calm stems from the fact that he has been a practising Buddhist for nearly 30 years and takes his faith seriously.

Buddhists believe in creating their own karma, so when I apologise for looking at my watch to check the tape recorder times, he keeps his gaze in the middle distance and drones: "You chose the job you got. If I'm boring you, I don't really care."

It certainly is not a good moment to float my theory as to why so many actors become Buddhists - because they get to look in a mirror while they pray - but I have to remonstrate when Duffy states in his self-satisfied way that he has always been a "passionate and emotional guy".

If this is true, why is he behaving so differently today?

"That is not my job," he beeps.

But he seems so very controlled and robotic...

"That is my job," he beeps again.

After Dallas ended in 1991, Duffy spent seven years appearing in a successful American sit-com which was not shown over here. Since then, he has made three television films but has settled into a life of "semi-retirement" and is shortly to leave California to live with his wife on their new ranch in Oregon. "Quite honestly, I think the industry needs a Patrick Duffy recess. I haven't stopped working for over two decades," he says. More importantly - much more importantly - he wants the time and the space to welcome in his old age.

"I really relish the ageing process. I can't wait to be 90 years old. And I like my diminishing strengths because they were taking up space for other strengths, ones which only age and maturation can develop," he says.

What he seems to mean by this is that now he no longer goes to the gym - "my pecs get softer every day" - his physical deterioration is creating a vacuum that his expanding brainpower can fill.

Even Patrick Duffy is coy enough not to refer to this as wisdom, preferring the marginally more humble description, "My accumulation of knowledge". For example, "My wife and I have an extremely modest but important art collection," he says. "And I now enjoy the ease with which I can sit and study an artist. You know, there is so much to learn about those guys."

However, it would be wrong to assume that Duffy is going to drift off to his ranch on a cloud of tranquillity and see out his days thinking great thoughts. Underpinning much of his conversation about his work is the murky discontent of someone who suspects that no one else takes him quite as seriously as he takes himself.

One of his projects will be an ambitious fictional trilogy of books, a prequel and sequel to The Man From Atlantis, that he and his wife are going to write. "If George Lucas can do that with Star Wars, then so can I."

During his years in Dallas, Duffy feels, he was at a constant disadvantage, as the scriptwriters were far keener to write good storylines for dastardly J. R. Ewing rather than for his boring brother, Bobby.

"They would be enthused and inspired when it came to J. R. but I was a functionary, something much more difficult for them to contend with.

"Bobby's sole role was to create value at the expense of his own personal happiness," he says, although I have no idea what he is talking about.

To get back on firmer ground, I ask if he believes himself to be a good actor. "I think I am good. I don't know if I am a great actor. I think I am a very good actor," he says, back in beep-mode once more. "I think I could be better if I was given different things to do."

Duffy grew up in Montana, where his parents owned and ran a bar. His father was an alcoholic who never quite conquered his addiction. "Dad would try to stop and he would, for a couple of months, but then he would start again."

After behaving like "the head buck in a rabbit warren, dating girl after girl after girl" throughout drama college, Duffy decided at the age of 21 that he wanted to settle down.

"I was deliberately, almost at random, looking for a woman, a wife. I was searching for something. I had personal problems," he says. Perhaps his own fractured childhood led to this unusually early desire for security, although he prefers a more poetic explanation. "I have an old soul," he says.

The woman he chose - "Carlyn, a ballerina I met on a bus" - happened to be 10 years older than him and already married, but nothing would deter Duffy from his destiny. "She has now been my wife for 28 years and is with me always, always," he says.

It was Carlyn who introduced him to Buddhism and both were happy to raise their own sons, now aged 25 and 20, in the faith. Certainly, it was Duffy's religion that helped him when his parents were murdered in their bar in 1986, shot dead by two drug-fuelled drifters. Afterwards, their son was much criticised for revealing that he had not shed a tear over their deaths. "My concept of death is different from most people's because I know it is the most inevitable thing there is. And because I believe that, people assumed a huge degree of lack of care and emotional commitment on my part."

Oddly, given his family history, he even laughs when he admits that his legacy from Dallas was a "finely honed" drinking habit of his own.

"I mean, I studied with the master. With Larry," he says of his co-star Hagman, who later needed a liver transplant. Their days on the Dallas set would begin when Hagman opened a bottle of champagne during the 7am make-up call.

"I would have a glass with him, but then he would continue for the rest of the day with many more bottles," he says. "At lunch, we would go off and find a restaurant, have a couple of drinks with our meal. Late afternoon before we wrapped, it was time for a little toddy.

"Then, after we wrapped, we would sit in the dressing room and have another little drink before we went home to have drinks before dinner and a bottle of wine with dinner and a little after-dinner drink before going to bed."

Was it fun?

"It was wonderful fun," says Duffy, who is a keen collector of first growth clarets, "but I couldn't keep up. I never thought, whoops! I'm developing a drinking problem. I just took my foot off the accelerator."

Saying that, he prepares to leave for rehearsal.

"The-automaton-is-done," he says larkily, as he makes his exit. You see, he does have a sense of humour - he just didn't want to share it with me. It must be my karma.

Patrick Duffy appears in Art by Yasmina Reza at Wyndham's Theatre, London WC2, from April 25 to July 16