Attention, shoppers: Lisa Simpson’s got a secret life! She works the register in aisle 9 of the local market, and she has traded her sax for sex — with The Wonder Years‘ Kevin Arnold. Well, okay, this isn’t a future Simpsons plot line. But watch Billy Crystal’s 39th birthday party scene in City Slickers and you’ll see the real mugs behind two of TV’s most popular mouthpieces. The voices of Fox’s precocious Lisa Simpson (Yeardley Smith) and the adult Kevin Arnold (Daniel Stern) on ABC come face to face — and then some. Stern plays Crystal’s friend Phil, a browbeaten husband who runs his father-in-law’s grocery. Smith is a sweet-faced cashier who crashes the birthday festivities, announcing that a pregnancy test from aisle 11 has produced some alarming news. Not to worry, though: Smith (as Lisa on The Simpsons) will be returning to second grade in the fall.