ENTHUSIASTIC applause provokes only the barest response from Nigel Hawthorne. The actor's pale, sharp-featured English face remains pinched in grief, the shoulders of his frumpy tweed jacket slumped during a curtain call. It is a woeful image in character with the role - that of the writer C.S. Lewis, who loses his wife to bone cancer in "Shadowlands," the play now on Broadway.

Later, backstage in his dressing room, Hawthorne is pink-faced and wearing freshly pressed denim and sneakers. But his gray eyes don't reflect satisfaction of a job well done, and he is testy in the face of well-wishers' small talk.

"It's very hard when people come around all bright and breezy afterward," he explains later, affability restored. "You get dreadfully involved [with the role] - if you shortchange the audience they can tell, so you have to do every single performance flat out. It's impossible to do that without getting emotionally exhausted, and I have to come out of it very slowly."

The 61-year-old Hawthorne grew up in South Africa, but considers himself an Englishman. Born in Coventry, he returned to Britain in the '50s, living most recently in the 400-year-old Hartfordshire farmhouse he shows off in a photograph sitting on his dressing table.

The actor has played a variety of roles, from Shakespearean characters to modern-day men, but on this side of the Atlantic, he is perhaps best known as the rather droll Sir Humphrey Appleby, that quintessential British bureaucrat, in the BBC television series, "Yes Minister," which is still airing on public television here. For the past year in London, before "Shadowlands" moved to Broadway, he has been portraying Lewis at a bittersweet period in the writer's life.

Before Hawthorne stepped into these shoes, he had only a passing acquaintance with his subject, a mid-century man of letters best remembered for his children's books, but during his lifetime a popular writer and teacher on Christian theology. Late in life, Lewis, who was known as Jack, married an American poet, Joy Davidman, played on Broadway by Jane Alexander.

"I didn't get on with his work a great deal; I'm not a particularly religious person," Hawthorne says. Lewis' was "that sort of muscular Christianity I find quite difficult. He was so sure of his beliefs, and I find that a bit off-putting." But what drew him to the play, "the joy of it," he says, "is that his beliefs are turned topsy-turvy and he's made to reassess."

In preparation, the actor read as much about Lewis as he could, assimilating "snippets of information. There are a lot of people around who remember him, who were taught by him, and I met some of those. A very close friend was one of the last people to see him alive."

"As in any role," he explains the process, "you have to make it as much of you as possible. If the part contains a lot of you - and I wouldn't do one if it didn't - then you draw on your own experience on how to behave in certain circumstances."

One similar thread is the two men's life-long bachelor status - until Lewis' short, belated marriage. Hawthorne says he, too, loves to write - although not on an autobiography for which he has a contract. "At the end of each page," he says, part-joke, part-modesty, "I say to myself, `so what?' "

Biographical roles are very difficult, Hawthorne says. "What you have to try and find is an essence. You can't possibly get the whole person, and if you did try, you'd be wrong. It's like Hirshfeld [the caricaturist] sitting down and doing a drawing. If he did it exactly as that person was, not only would it be dull, it would be lifeless - like tracing a photograph."

Sometimes, real-life acquaintances have found Hawthorne's portrayals uncannily righton. When he played Walter Monckton in television's "Edward and Mrs. Simpson," the Monckton family "made me an honorary member, gave me the Monckton family tie," Hawthorne reports with a chuckle. "Oddly enough, I've been most sharply criticized for fictional characters. I think sometimes when people read a book, their conceptions are so graphic that when the book is filmed, they can get apoplectic with rage about an interpretation that's given."

In the case of Lewis, Hawthorne says he looks nothing like the writer, but, as the play reveals, Lewis looked nothing like the usual image of an Oxford don. "He looked like a farmer," the actor discovered, "this sort of guffawing, cumbersome man with these hideous clothes. He wore these strange, floppy hats and looked a mess."

Just before "Shadowlands," Hawthorne was in Tom Stoppard's "Hapgood," "because it was strategic. He's a fashionable writer. But the role had no heart, so I was wrong to do it." "Shadowlands" was a wiser move: "The part is absolutely wonderful because it takes you on that journey: You see a man who appears to be one thing, and you see him become someone else."

Today, Hawthorne says, he's seen as a "prototype Englishman, which is a bit ludicrous" - and also ironic. "One of the reasons I didn't make a success as an actor in my early years was that I had had no regional background. When I was beginning, John Osborne and all these people [playwrights] were emerging and writing parts for people with regional dialects - these bright young things, the Albert Finneys and Alan Bateses - and the sort of character, the more refined manner I thought I possessed, was becoming old-fashioned."

It isn't that this type has flipped back into style as much "as I became middle-aged and started to recognize my vulnerabilities and incorporate them into what I was doing. It was a bright thing [to do] because we're all a mass of faults, and English people spend their lives trying to cover them up. There's a sort of closetness about people, and what I look and sound like seems to coincide with this characteristic. So I'm able to be hurt, to be pompous, to expose myself to danger, to go in where angels fear to tread and be smacked in the face."