Self-effacing to the point of disappearance, Derek Jacobi likes to down-play the difficulty of performing two plays, two utterly contrary roles, in the space of a single day. "It's a knack you acquire, doing repertoire theater," he says simply. Having just completed a dazzling 3 1/2 month run of Broadway, Jacobi and the Royal Shakespeare Company are in the midst of a month-long engagement at the Kennedy Center in Washington. There, as in New York, matinee days can be pretty daunting: at 5:30 Jacobi walks off the stage as Cyrano de Bergerac, Edmond Rostand's swaggering, swash-buckling hero. Two hours later, showered and recostumed--Cyrano's huge latex nose discreetly removed--he returns to the stage reincarnated as Benedick, Shakespeare's reluctant lover in 'Much Ado About Nothing.'

Certainly the two productions could not offer a starker contrast: Shakespeare's sparkly, screwball comedy treats wit and word play as defensive weapons, obstacles to heartfelt passion; while Rostand's tragedy equates love with style, with the eloquent manipulation of words. The heros of the two plays, too, are consummate alter-egos: Benedick, the tart-tongued skeptic, who proclaims himself a bachelor for life; and Cyrano, the purple-tongued romantic, who will risk his life for his sweetheart or a cause. For Jacobi, these roles demand two very different techniques: the emotionally reticent Benedick calls for a "personality performance, where I'm working off my own center"; Cyrano, a "character performance, where I have to find areas of rage, anger and a fierceness that are not part of my surface personality." With Benedick, he says, he is playing a version of himself; with Cyrano, someone he admires, would like, ideally, to be. Poet, philosopher, duelist and soldier, Cyrano is the sort of fellow who can rattle off heroic couplets while single-handedly dispatching an entire band of villains with his sword. If he is too ugly to win the hand of the lovely Roxane, then he will use his eloquence to woo her for a rival, letting his own feelings pour out in ringing streams of verse. In playing Cyrano, says Jacobi, "you have to have a bombastic freedom of emotion, where the emotion is oozing out of your fingertips. If he thinks it, he says it. If he feels it, he shows it. Cyrano has a panache, a dazzle, an up-front, out-front, look-at-me swagger that doesn't come naturally to me."

What comes naturally to Jacobi is "don't look at me--look at him." He says he is gentle where Cyrano is tough; timid, where Cyrano is angry and assertive. He admires those actors acclaimed for their "sense of danger"; envies others famous for their temper tantrums offstage. As for himself, Jacobi says he goes to herculean lengths to avoid confrontations and scenes. "I don't think I'm a very strong character," he says wistfully. "I am dull, wishy-washy, indecisive, untemperamental. My emotions are under the carpet. I'm told I have a great facility for switching off. Friends say, 'Oh, he's gone, he's gone.' They see a look in my eyes, and they know I'm not around anymore. I guess it's a kind of defense. In many ways, I guess I'm very much like Benedick, who almost never shows his feelings--until the end of the play."

Like Benedick, Jacobi uses his "advanced sense of humor" to hide his real feelings. And like Benedick--who experiences himself as a bachelor in a world of couples, an adolescent court jester in a world of grown-up concerns--Jacobi suffers from a sense of being an outsider, someone more at home in the world of the imagination than in the real world. In fact, it was this capacity for dreamy wonderment, combined with a terrible insecurity about "who I am, where I'm going and why I'm here", that gave him a craving, an "absolute need" to act. On stage, he feels "in command--much more than in real life," because he knows who he is supposed to be and what is supposed to happen. On stage, he finds, he can somehow "ennoble all the sad, distressing things that happen to you in life."

"It's a great panacea, acting. You can transform an emotion that was originally a hurtful one into something very soothing. For instance, my mother's death several years ago was hugely traumatic for me. And yet on stage, if I can recall what it did to me at the time, it's no longer hurtful inside. It's a kind of purging process."

"Extraordinary things happen up there on stage. Like today, I have a cold. I'm not feeling on top of the world, but I know tonight I have to go out there and play Benedick. The audience hasn't come to see a guy with a cold, and hopefully that's not what they'll get. My cold will be back here, waiting for me in my dressing room when I return,..but out there, it's magic land. I know that sounds childlike, but perhaps I never learned to grow up."

When he was starting out as an actor, Jacobi recalls, Laurence Olivier once offered him a piece of advice: "Find your own center, both as an actor and a person." What he meant, says Jacobi, is that while acting involves putting on various disguises, each character must be filtered through "the force that is you--otherwise you're playing a creature with no heart, with no insides." Though his "feet are now more firmly planted on the stage," Jacobi says he has yet to discover that "essential me." He worries that he lacks the sort of presence that gave old-time movie stars the ability to stamp a role as their own, and adds, a bit wistfully, that he hopes he "can make up in versatility what I lack in charisma."

Because he is so insecure about the forcefulness of his own personality, Jacobi actually finds it more difficult to play a character, like Benedick, whom he feels close to, than one like Cyrano, who offers a blank slate. "If you're taking the role off yourself, you're limited by your own personality. And you have to be very confident about what you're doing. I'm not, so I find it very difficult to project myself to the audience. It's also dangerous playing someone like Benedick, because you can enjoy yourself too much. On occasion I've just forgotten about him, and it becomes me up there, having fun. Particularly in the soliloquies. It becomes you, talking to the audience, being chummy; and that distracts the audience from the total concept of the production. When that happens, I have to say 'stop it, stop it. You're being self-indulgent.'"

No such problems exist with Cyrano--a character who demands a complete leap of the imagination, a character who gives Jacobi the chance to "hide behind various things," and also leaves him "more susceptible to inspiration." In developing his portrayal of the blustering soldier of fortune, the actor says he relied heavily upon suggestions made by the show's director, Terry Hands. Apparently Hands not only suggested possible interpretations--it was he who focused on the character's huge capacity for anger--but he also tried to goad Jacobi into giving a superior performance by appealing to his fears. As Jacobi recalls, "Terry said, 'You're not a born Cyrano, so we have to justify the casting. If you don't get Cyrano right, It'll set your career back years.' It was very painful for me at the time, but it ended up broadening my range as an actor."

As rehearsals continued, Jacobi began to discover aspects to Cyrano that were readily sympathetic, and in the process, he also found affinities with Benedick. The men in both plays, after all, are essentially loners, isolated from their fellows by temperament and condition, And both, in a sense, are actors who use masterful histrionics to protect their inner selves. Just as Benedick hides his love for Beatrice behind volleys of sarcastic banter, so too does Cyrano conceal his vulnerability and thwarted love for Roxane beneath his noisy displays of bravado.

Having become famous playing the crippled emperor in television's 'I, Claudius', Jacobi points out that he is fascinated by "the sort of people who look one thing, behave one way, and who are something else inside." The emotional consequences of physical appearance are also familiar to him firsthand, for he suffered, as a teenager, from "the most appalling acne." "I either dared people to look at me, to focus on the boil at the end of my nose," he recalls, "or hid myself away. So I kind of know how Cyrano felt. Also, I am in a business that is very much a business of beautiful people, where beauty can open many doors and lead to many rewards."

In physique, Jacobi himself is slight, not very tall; in demeanor, boyish, round-faced,..impish rather than domineering. It is a fact, he says, that used to be the source of considerable worry. "I've always had this thing that people will only accept you in a suffering role if you look as though you suffer. Hamlet's got to look as though he suffers. Now, if you look like me, you don't look exactly tragic. On the other hand, if you're darker, thinner, with sunken cheeks, you look haggard, harrowed. It's a very subtle difference, but I'm sure it's there in people's minds. That's why I love putting on makeup, changing myself to go on stage."

"I need acting like blood," he goes on. " I come to life out there. How can I put it?--I can say I exist because I am an actor, not the other way around."