Jessica Alba is zipping her lip over whether she's batting a thousand with New York Yankee shortstop Derek Jeter. "I don't talk about who I'm dating," the in-demand actress tells the New York Post. "It's very hard to have a functional relationship. You have to keep it as private as possible no matter who you are." Alba, who's been hard at work on the highly anticipated Robert Rodriguez flick "Sin City" and just inked a deal to play Sue Storm in "The Fantastic Four," has reportedly been seeing Jeter since mid-June. The "Honey" star, who was spotted last week signing baseballs at the Tigers-Yankees game in Detroit, was previously engaged to her "Dark Angel" co-star Michael Weatherly, while Jeter's long list of exes includes Mariah Carey.