Will & Grace - Season 6 Episode 23 I Do (1) Where there's a Will there's a Grace.
Overview: Opting to forgo a picturesque fall wedding to elope in Las Vegas, Karen hops a plane to ""Sin City"" with fiance Lyle and faithful friends Will and Jack but when she bumps into vacationing superstar Jennifer Lopez, she asks J-Lo to sing at the ceremony. Meanwhile, Leo returns from Cambodia to meet up with Grace at the wedding, but their reunion is delayed by a freak design accident.