Which First Lady of the United States made a guest appearance on the U.S. TV sit-com "Diff'rent Strokes"?

Loved the show. But unfortunately I don't think Nancy got through to many.

The "war on drugs" made many politicians wealthy. Many LEO's too. The "oldest profession" would not be possible without said drugs...few volunteered. The (sad) contributions to our economy are inestimable. Not at all pro drugs.