In Diane White-Clayton's version of Bethlehem, the sheep like to rap.

Plus, the shepherds are bluesmen, none too happy about spending another cold, lonely night at work — until they happen to notice a very unusual star.

White-Clayton thinks a lot of people could imagine that. She trusts that one of them could have been poet and playwright Langston Hughes, author of "Black Nativity."

The Black Rep is presenting the holiday classic once again this season, the 20th anniversary of its first production of the play.

White-Clayton is the show's music director, just as she was in 1989. Back then, she was a talented novice. This time, with a doctorate in music and years of professional experience behind her, she is not only the show's arranger but the composer of many of its songs. Besides rap and blues, she includes spirituals, traditional and contemporary gospel, classical pieces and modern, atonal work.

The music is incorporated into Hughes' play, which employs song and dance to tell two stories. The first act relates the Nativity according to the gospel of St. Luke; the second act finds us at a black church celebrating Christmas.

That, White-Clayton observes, is a pretty big stretch; she thinks the music requires just as expansive a range. "When Langston Hughes created 'Black Nativity,' he wrote the text and just threw in traditional songs," she explained. "There was no score. So every time it's performed, it's something new and different."

Impossibly tall and slender, the 44-year-old artist cuts a dramatic figure onstage and off. A singer, pianist, arranger, composer, music publisher, church choral director, author, teacher and lecturer, "Dr. Dee," as friends call her, leads an extremely full life in Los Angeles with her husband of two years, percussionist Joe Clayton. (It is her first marriage: "I waited for the right one," she says. Now semi-retired, Clayton played on the early Jackson 5 hits, as well as with Marvin Gaye, Barry White, Nancy Wilson, the Osmonds and many other recording artists.)

But when the opportunity to return to the Black Re presented itself, White-Clayton jumped at the chance.

"I just wish I could have been in this show, too!" she exclaimed, flashing her generous smile. "I love to act and to sing — well, I wear a lot of hats."

This one suits her now, because "Black Nativity" marks a kind of homecoming.

White-Clayton, who grew up in Washington, had barely heard of St. Louis when she won a big scholarship to study music composition, voice and piano at Washington University. Before she had graduated, Ron Himes — the Black Rep's founder and producing director — asked her to arrange music for its next show, "Eubie."

"We enjoyed working together," she recalled, "and (the first production of) 'Black Nativity' came next." That was in an old North St. Louis church, home to the Black Rep for years.

"When I first walked into the Grandel Theatre, all I could think was, 'Ron, you have come a long way!' It's so rewarding to come back and see how this company has grown."

It is, she says, humbling to "collaborate," in a sense, with Hughes, the famed African-American writer probably best remembered for his poem about "a raisin in the sun."

"But I trust Ron's artistic genius and I trust that if he asks me to do something, I can and will do it," White-Clayton said. "With 'Black Nativity,' we are trying to give expression to all the art forms most essential to the African-American experience."