Among the many gifts that Kate Pfaffl displays in War Horse, in her role as the Song Woman, the most impressive may be this: her ability to play the violin, sing, and roam the stage - simultaneously. "There's a lot of brain function going on at that point," Pfaffl told me the other day in her dressing room before showtime. 

"It's hard enough to sing and play the violin at the same time," said Pfaffl, who took up the violin at age 6 (Suzuki method) and after high school (where she was a competitive classical pianist) studied voice and musical theater at the University of Cincinnati, Conservatory of Music. "Because when you're holding the violin with your neck, it closes off your larynx and you have to breathe from a different place." Pfaffl continued: "When you have to walk at the same time your breathing is further affected. To prepare for this role I would walk around the house for hours while I played the violin and sang. The challenge onstage is not to focus on any one of these activities. If you do, everything will fall apart." 

My conversation with Pfaffl, who grew up in Milwaukee, covered not only brain function but the function of her character, the Song Woman, in the play. "It's interesting for me which characters I echo, which I influence, and which I am connected to," she said. In the six songs she sings (sometimes quite fully, sometimes in reprises and snippets), she appears to be mother or sister or daughter. "I stand in part for the women that the soldiers have left behind." 

This is a revised take on the character, who, in previous productions of War Horse, in London, was played by a man. (The LCT production also has a Song Man, portrayed by the wonderfully gifted Liam Robinson.) "Because I'm the first woman to do this role," Pfaffl said, "there had to be a shift, a rethinking. We had to create a more ethereal character for me, not so much of a soldier type." John Tams, the production's songmaker and an authority on traditional English folk music, told Pfaffl that in Devon a century ago, when War Horsetakes place, it would be unusual for a woman to perform publicly the kind of music assigned to the Song Woman. "My character would more likely be a kind of gypsy," Pfaffl said, "a traveling storyteller." 

Pfaffl says she's happy that, under the influence of Tams and of War Horse in general, she has discovered a connection to folk music. "As a singer/songwriter" - she has just released her fifth CD, titled Mighty Kate, after her club-performing moniker - "I'm more into pop and rock." (Her website is www.mightykate.com). "But I've found a new, folk-loving side of myself. The music is simple and honest and raw, and I love that. It's a sound that works very well for the Song Woman, who is the play's emotional narrator." 

Performing the songs in War Horse not only taps something deep in Pfaffl's psyche: "They have such a deep groove," she said, "that when I go to sleep at night I still hear them turning over and over in my head." Those songs have also helped her rediscover her roots in theater. "For so long now I've been living more of a singer/songwriter life - one-night gigs here and there - that I'd almost forgotten how enriching it can be to be performing in a play or musical. I'm grateful to War Horse for giving that feeling back to me." 

The experience of the play has also allowed Pfaffl to relate to her students - she is a vocal teacher and coach at New York's Voice Studio, where in part she helps actors prepare for musical-theater auditions - in a new way. "My students can now see and hear that their teacher is the real deal," Pfaffl said, laughing, "and not just a hack." 

Pfaffl has a final reason to be grateful to War Horse: it has led to a discovery about her family history. "I had no idea what my maternal grandfather had gone through in World War I," she said, "or, to be honest, that he had been in that conflict at all. I just thought he had been 'in the war.'" In talking to her mother about the play, however, Pfaffl learned that not only was that grandfather an American soldier in World War I in France, where War Horse battles occur, but that, at the age of 18, he had been gassed. 

"He had been left for dead," Pfaffl said. "He was rescued by a French man, who nursed him back to health. He died before I was born" - of cancer, likely linked to his having been gassed - "but I think about him a lot. I wouldn't be standing on stage at Lincoln Center performing in a play about narrowly surviving in the First World War if my grandfather hadn't narrowly survived the war himself." 

Brendan Lemon is the American theater critic for the Financial Times and the editor of lemonwade.com.