Marcia Haydee, new director of the Stuttgart Ballet and the company's most noted dancer as well, may be unique among ballet women in simultaneously filling the roles of star performer and artistic guru.

In retrospect, it looks like a fated occurence. Haydee is not just a superb rancer, but an exceptionally polished ballet actress as well. She rose to prominence in roles like Juliet, Kate in "Taming of the Shrew" and Tatiana in "Eugene Onegin," parts created expressly for her by choreographer John Cranko, whose histrionically elaborate "story ballets" put the Stuttgart troque on the international map. What's more, for 13 years while Cranko was still alive, she was his close friend and confidante.

"I think that unconsciously Cranko was preparing me," she says now, "for the eventually of directing a company. we always used to sit and talk together, about making plans for the company, about castling, about emerging young dancers. And he knew I enjoyed these things."

Classical ballet is one of the few professional fields in which women have reigned among the high and mighty for a long time. Aside from the illustrious ballerinas of past and present, women such as Lucia Chase of American ballet Theater, and in earlier years, Ninette de Valois of England's Royal ballet and Celia Franca of the National ballet of Canada, have aslo been directors of major ballet companies. But Haydee alone, by the kind of dancer she is, by the forthrightness of her personality, and by her singular relationship with Cranko, was groomed by destiny for the double assignment she has undertaken.

"It took me a while before I was completely able to disconnect the two functions," she said at the Kennedy Center yesterday, preparing for the company's opening tonight of a three-week engagement at the Opera House. Haydee herself will be dancing the leading role of Taitana in John Cranko's evening-long "Eugene Onegin," with Richard Cragun as Onegin, Egon Madsen as Lensky and Reid Anderson as Price Gremin.

"I would be in class," Haydee said, "and find myself thinking, oh, this Romeo, I must cast this dancer and that dancer, and then suddenly I see another dancer in class I was just a dancer and that outside I would be making these decision."

Her transition to the dual responsibility wasn't as trying as it might have been for several reasons. The Brazilian danger came to Stuttgart as an unknown in 1961, the year John Cranko first took over the directorial post, and she grew in stature and reputation as Cranko created role after role for her. After Cranko's sudden death in 1973 at the age of 46, the American choreographer Glen Tetley assumed the helm. But after a relatively stormy two years, Tetley resigned, and almost by acclamation, Haydee bacame his successor.

"The company itself was very optimistic when Tetley arrived, and there was no strain within the ranks," haydee recalls. "But the press and the public in Germany gave him a very hard time. Cranko was like a god to the Germans. It made it very hard for Glen to build his own repertoire; he didn't feel free to be himself in his choreography under these circumstances."

Nevertheless, Haydee maintains that the company learned much from Tetley, and notes that all the works he staged or created for Stuttgart have been retained in the repertory (his "Voluntaries" will be seen this week at Kennedy Center). "We learned a whole new way of moving - Tetley's involvement with modern dance gave us a new freedom, a new artistic dimension that carried over into the rest of the repertory as well."

Haydee's own reception as director from the German press and public has been gratifyingly favorable. "I was a product of Cranko, and they knew I would follow in his path. I believed in Cranko's way so much, not that it's necessarily right for every company, but for ours I think it is the only one. Cranko believed in developing dancers as individuals. He didn't want just a corps de ballet with no faces, soloists with all the same style and personality. He let each one of us go our own way. And he always took risks, because he sought to encourage younger dancers - and younger choreographers."

Haydee finds that wearing two hats, far from being a hindrance, is actually a help to her in more ways than one.

"The more I have to do, the more stress of time I'm under, the better it is for me. If I have too much time, I start worrying, or rehearsing too much. And now, being a director, instead of being anxious about my own dancing, I have to worry about everyone else, and the result is that I'm more relaxed in my own performance. I learn from the other dancers, too. Watching them take over roles I've done, I see new angles to them; it freshens my own interpretation. On the other side, being a dancer helps me as a director - I still think like a dancer, I know what dancers need and what they want.

"The company helps me too. They're very special kids. In class, if they see I'm concerned about my own performance problems, they leave me alone. Because they're individuals, they're very self-reliant; they take over when I'm under a strain. They say, don't worry, do your own work, we'll be all right."

"The fact is, no one person can be aware of everything all at once, so I rely on the company's help," Haydee says. "Sometimes you think you have your eyes open and can see everything, but there's one little corner you miss. It's like cleaning up - you clean and you clean, and suddenly you remember, omigod, I forgot to clean behind that table."