SPRING GREEN, Wis. -

American Players Theatre, I think, has a new star.

Cristina Panfilio, a Chicago actress making her debut with the Spring Green repertory Shakespeare company this year, takes a leading role in APT's "Twelfth Night" and runs away with it.

The play is a typical Shakespeare comedy. It involves twins, a brother and a sister, who are shipwrecked, each believing the other is drowned.

The sister, Viola, disguises herself as a boy and becomes a page for Duke Orsino of Illyria and falls in love with him (why, I have no idea). Orsino, however, thinks Viola is actually a boy named Cesario (he isn't too swift) and sends him/her to woo the Countess Olivia, who, in turn, falls in love with Cesario.

Got it?

The thing is that Panfilio actually pulls this whole thing off. She is convincing as Viola. She is convincing as Cesario. She actually makes one think she is fascinated by Orsino, dolt that he is.

The reason why, I think, is that she never steps out of character. Even when the action is on the other side of the stage, her sometimes fleeting facial expressions are what one might expect if the attention had suddenly turned to her.

I go into this only because it is unusual for a new actor to so dominate a role at APT.

There aren't many Shakespearean venues in this country and anyone the theater hires is almost by definition going to be extraordinary -- so most performances are pretty equally talented.

And there certainly was nothing wrong with the other actors. Susan Shunk -- who similarly dominated "The Glass Menagerie" last summer -- was a fine Olivia. Marcus Truschinski was a bit stiff as Orsino, but, then, Orsino is a bit of a stiff. Mark Goetzinger was wickedly funny as Sir Andrew Arguecheek, an idiot with aristocratic airs.

And, to be honest, my favorite performer of the evening was Sarah Pickett, the musician, who spoke not a word but kept popping up here and there playing a variety of instruments.

But if I was going to see the performance again, Cristina Panfilio would be the reason why.