In a rare joint interview with ''Access Hollywood'' host Pat O'Brien on Thursday's ''Dateline'' on NBC, Jennifer Lopez and Ben Affleck reveal that Affleck's best man will be his brother Casey (''Ocean's 11'') and not best bud Matt Damon. As for who's designing her gown, Lopez says only, ''I'm having something made.''
Whenever it happens (the pair didn't specify a date), Lopez says she won't mind if they're besieged by paparazzi. ''If people want to be outside and they want to take our picture, then OK,'' she tells O'Brien. ''We're not going to be with the 24 million security guards. We wanna be just like -- have a nice wedding ... have it be a beautiful day... and if there happen to be cameras outside, then that's fine. We're not gonna obsess over them.''
O'Brien, who taped the interview last weekend at Affleck's rented home in Vancouver (the actor is shooting the John Woo thriller ''Paycheck'' there; his fiancée, who's shooting ''Shall We Dance'' with Richard Gere in Winnipeg, flies across Canada every weekend to be with him), played basketball with Affleck, and restaurateur Lopez (who owns the Caribbean eatery Madre's in Pasadena, Calif.) cooked them all a traditional Puerto Rican supper. ''You haven't lived until you have Jennifer Lopez cook you dinner,'' O'Brien says. He says the interview reveals ''who wears the pants in the family,'' and apparently, it's not homemaker J. Lo.
Lopez says her go-with-the-flow attitude even extended to her work on ''Gigli'' (in theaters July 30), where she and Affleck traded ad libs. ''It felt like we had good chemistry,'' she tells O'Brien. ''He liked to improv. I could improv back. He's the best person to improv with in the whole entire business, really.'' Affleck interjects, ''Don't be like my mom. Don't do that thing where you're like [in a mom voice], 'He's the best, he's so good at...''' ''He is, though,'' she says. ''For real.''