The writer Paul Rudnick once told me that on the set of the movie Addams Family Values, for which he wrote the screenplay, the most poised member of the cast was Christina Ricci, age 12 at the time of shooting. Several adult cast members of War Horse have told me that on their show the most poised member of the cast is also age 12: Madeleine Rose Yen, who plays the French farm girl Emilie. Based on a chat I had with Yen outside LCT on the plaza the other day, a conversation in which Madeleine's mother, Julie Yen, participated, I have to say that I understand what Madeleine's colleagues mean.

Attired in a lovely white-print summer dress, and with her hair in the kind of French braid one doesn't see much anymore, Madeleine told me how she got into show business. "I saw 42nd Street on Broadway when I was 4," she said - an outing, her mother put in, that was arranged because even at that age Madeleine loved tap dancing. Lessons in ballet and tap for her soon followed. Madeleine's current teacher for the former is ballet star Elizabeth Parkinson, known to theatre audiences from Movin' Out; for the latter, Madeleine studies with Parkinson's husband, Tony-winning performer Scott Wise. "I haven't been able to take their classes lately, because of War Horse," Madeleine said, "but I'm hoping to return." 

Madeleine, whose maternal great-grandfather was in vaudeville and whose maternal great-grandmother was an actress, made her stage debut in a community-theater production of A Midsummer Night's Dream. Her career kicked into gear, however, when she auditioned for a showcase in Tarrytown, New York, and was seen and signed by a manager. Madeleine was eight. 

Since that lucky break, Madeleine, who has an older brother named Joseph, has provided the voiceover in French's Mustard commercials and appeared in ads for Bank of America. She is also a series regular on the Nickelodeon show Team Umizoomi. "My Broadway debut," Madeleine informed me, "came in White Christmas, in 2009. I had already done the show the year before, for a whole month, in Detroit." 

By now you are probably wondering how a child manages to do eight shows a week, in Detroit or New York or East Podunk, and maintain her status as a student. "Madeleine has been home-schooled since kindergarten," Julie Yen informed me, "so we have a little more flexibility with class time than we would with a regular school." Added Madeleine: "There are other people inWar Horse who were home-schooled - Seth [Numrich], Ariel [Heller] - so I'm in good company." 

The experience of War Horse itself has been a year-long curriculum for Madeleine. She said: "During rehearsals for the show I felt I was learning something exciting every day. Tom [Morris] and Marianne [Elliott]" - the production's directors - "gave me assignments to understand my character better. One time, I had to draw the kind of house that Emilie would have lived in." 

Madeleine, whose character's family is under constant bombardment, also learned about munitions. "I couldn't believe how heavy some of the shells were - they weighed between eighty and 150 pounds." Madeleine also read the Michael Morpurgo book on which War Horse is based. "In it, Emilie is older than me: she's 15." 

Before her current job, Madeleine said that she had ridden a pony but not a horse. "Once Madeleine got a call-back for the part," Julie Yen commented, "we took her riding." 

"The horse I rode," continued Madeleine, "was an auburn one named Pixie. Pixie had a mind of her own: every so often, she would stop and jerk forward. I learned that every horse has a personality." 

Madeleine said that Joey, the main horse in War Horse, also has a distinct personality, but that it changes depending on which of the three groups of puppeteers who rotate the assignment - three actors each - is performing. "Some make Joey more feisty, others make him more sweet. And Joey's nose-blowing also changes: sometimes, it's powerful; sometimes, it's not." Madeleine has no favorites among the horse puppeteers, nor among the cast itself. "It's a family, and you love them all," Madeleine said. "I'm so lucky to be in this play." 

The only time during our conversation that Madeleine made a Joey-like turn from sweet to feisty was when the subject of very young children attendingWar Horse came up. "There was a little girl in the audience the other day," Madeleine said, "who was acting up. I wish all parents would realize that War Horse is not a play for really little kids. It's intense!" Madeleine is grateful, though, for the older children who tell her how much they enjoy her performance in the production. "When you're a kid it's really cool to be in the audience and watch a kid your age performing," she said. "You understand where they're coming from." 

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