Q In Crossroads, Britney Spears dons a Southern University T-shirt. Southern's a predominantly black school in Baton Rouge, La. What gives?

A Costumer Wendy Schecter, who found the tee at an L.A. thrift store, explains: ''Her character, Lucy, is a college-oriented girl.'' The snug shirt was a perfect fit. Spears is from Kentwood, La., 75 miles from 17,000-student Southern's main campus. The school wasn't T'd off. ''We're tickled pink,'' says chancellor Edward Jackson, who approved the placement. ''The fact that we're African-American makes little difference.'' The school bookstore is seeing another color -- green. Sales of Southern duds are up.