They began to behave out of character, logging on to BBC message boards to chatter excitedly about the wonders of RA, as they quickly dubbed the 34-year-old actor. In the end, the volume of chat was too great, and the BBC closed down the North & South message board. Undaunted, the devotees, calling themselves the Armitage Army, set up their own website.

Armitage's next appearance is in The Impressionists. As Claude Monet, he dominates a storyline that follows the young French artist and his friends Renoir, Degas, Cezanne et al as they battle the Parisian art establishment to gain recognition for their revolutionary painting methods. How will the Armitage Army respond to this new part? It's hard to imagine that the artist's straggly wig and creative twirls of facial hair will provoke quite the same response as the magnificent Mr Thornton.

In the flesh, Armitage is charm itself. He is tall (tick), dark (tick) and handsome (tick), with piercing blue eyes (double tick). Ladies, your swoons have not been wasted.

He says he has taken the decision not to read the message boards set up in his honour. ?When North & South came out, I did have a little look, " he admits, ?but I stopped quite quickly. I was aware of that thing of believing in your own hype. I didn't want to start thinking that I mustn't do this role or people will be disappointed."

Might he not have donned the Monet wig otherwise? ?I hadn't thought about that, actually. I suppose it's not that attractive, all that hair and a funny beard, but when you're working from somebody real, you don't really have a say."

I can't resist quoting one example from a message board, an ode written in his honour. ?There's been casualties from ovaries exploding/ And an awful lot of thudding! / Richard only has to start his irresistible brooding/ And we all start imploding!"

?Noooooo, " he wails, looking genuinely embarrassed.

?What I don't get is that I didn't write the character. I suppose I get the attention because the author's dead. If Elizabeth Gaskell were still alive, they'd write to her, I think." Oh, really? I don't think the clergyman's wife from Manchester would have provoked such panting poetry.

Besides his charming modesty, Armitage does display a strain of business nous when he talks about ?the Thornton effect". ?It's incredibly useful to future employment. When you already have a following, people are more likely to employ you. The role definitely put me on the map a little bit, so people know I can do a certain type of part. It's opened some doors to me, but there are lots that are still closed , , it's circles within circles. I'd love to work more in films, for example."

Armitage Army members are no longer confined to Britain. His website's guestbook contains adoring messages from Japan, Russia, Australia, the US and more, as the drama gets sold to broadcasters around the world. The website features a message from Armitage thanking the fans for their support but warning them that any more gifts sent to him will be forwarded to his local shelter. The most memorable gift so far is an enormous pink blanket, handcrocheted by a woman in Germany, who also sent pots of jam and honey. ?That blanket kept my agent's knees warm for a while before I had a chance to pick it up, " he says with a wry smile.

Armitage describes himself as reluctant rather than shy when women approach him in the street. But without Thornton's top hat and cravat as a visual clue, he mostly passes unnoticed.

Surprisingly, he has failed to capitalise on the fact that he has thousands of admirers.

Surely he is missing a trick.

?There's nobody in particular in my life at the moment, but I have had a few dates, " he says.

?I'm a bit of a recluse, a bit boring, really." He looks up, worried. ?Am I painting myself as a total loser?"

This non-loser grew up in a Leicestershire village, an ordinary child with a passion for stories. He attended drama school in Coventry and then joined the circus to get his Equity card before taking the more conventional route of touring in local theatre and receiving a classical education at Lamda.

It was there that he spotted a request on the noticeboard for tall men to play fighter pilots in Star Wars: The Phantom Menace. ?I got incredibly nervous on the set and delivered my one line very carefully. I wondered why the crew were looking at me strangely, but when I watched the film, I realised my voice was completely computerised.

I'm in one of those blooming white outfits with my face covered up."

His other lasting memory from the set was chatting up a beautiful young actress whom he believed to be Natalie Portman. She nodded politely as he called her Natalie over and over again, but when she stepped forward for her scene, Armitage realised she was Portman's body double, an unknown British actress by the name of Keira Knightley.

For The Impressionists, Armitage and his fellow actors received training from an artist on how to hold their brushes and how to paint on camera. ?Monet was like a conductor. He painted with quite a straight arm and used bold strokes." The actor took advantage of a gap in the hectic filming schedule in Provence and Normandy to visit Paris and see as many original Monets as he could.

?What I knew of Monet came from coasters and placemats and pencil cases. They don't bear any resemblance to the original paintings. They get so overused that you don't appreciate them for the works of art they are."

Next up for this heart-throb du jour is a role as Guy of Guisborne in Robin Hood, a BBC drama that is scheduled to fill the precious Saturday teatime slot occupied by Doctor Who. And, as with all promising British actors, Tinseltown beckons. He's been to a Los Angeles audition for a role as a CIA agent in a television pilot. Armitage tells a story about his casting session that just about sums up this man's pleasing blend of confidence and modesty. ?I'd practised my American accent really hard so I could get the part just right. When I finished reading, the casting people said, 'Wow! That was great. . . Now would you mind doing it again with an American accent?'"