ANT artistic director Peter Sellars was taken on a new role -- but it's not clear if it's a bad or a good one. He played a part in a segment of "Miami Vice" filmed last week. "I think I'm a good guy," he said. "It was a real hoot." And why add acting to his host of duties? "It's important to be well rounded," Sellars said. He doesn't know when it's going to be shown.

Ford's Theatre has gotten a $100,000 gift from the Sun Co. to underwrite a large part of the preproduction expenses for "Little Me," which will replace "A Christmas Carol" as this year's holiday production. Based on the book by Patrick Dennis, the Neil Simon/Cy Coleman collaboration was first produced in 1962, starring Sid Caesar. James Sudik will play the lead here . . . Charles C. Welch, best known to the public as the twinkly codger in Pepperidge Farm commercials, has agreed to star in the Reston Community Players' production of "Finian's Rainbow." Welch, an old friend of board member Shelton Hall, will appear in the community theater show under an Equity Guest artist contract . . .

Playwright and director Harold Pinter is supposed to join the cast of his "Old Times" when it opens a week's run in St. Louis next Tuesday. Liv Ullmann and Nicola Pagett are the women in this production, which is going on to Los Angeles and San Francisco . . . The Jack Lemmon production of Eugene O'Neill's "Long Day's Journey Into Night," which comes to the National in March, will try out in the quiet academic environment of Duke University, where producer Emanuel Azenberg is a visiting professor, Variety reports.