"I've been doing this for three years, and I am always shocked at the demands of the show," said Mulgrew last week by phone from her New York home.
She brings Tea at Five to the Shubert Theater this week and next, a return to the Boston area where it had a successful run at American Repertory Theatre inCambridge two seasons ago.
Matthew Lombardo wrote the play specifically for Mulgrew after her best friend, the late Nancy Addison, suggested it.
"They knew each other and were watching me on Star Trek: Voyager (where she played Captain Kathryn Janeway for seven years). I am sure they were laughing.But then he said 'I think she'd be a great Hepburn.' And Nancy said 'why don't you write it for her,'" recalled Mulgrew.
That is precisely what Lombardo did, firing off a script in three days and sending it to Mulgrew. She loved it from the start.
"I instantly grasped what he'd done, following her life from young to old," she says.
What makes Hepburn so fascinating is all that is hidden and all that has been revealed about her, says Mulgrew.
"It was her deepest heart that she hated exposing. She was hurt when she was young and was so compelling and vulnerable. That, I think, was the real Hepburn. She was an amazingly complex person, and playing her brings out somuch grief, pain and joy," says Mulgrew.
Mulgrew, whose credits include many TV shows and films, says doing a one-woman show is "rigorous, lonely and terribly challenging. I often feel like I amflying without a net. But that's why I got into acting in the first place."