 In the episode , Jack ( Sean Hayes ) begins a rivalry with a fellow named Owen ( Matt Damon ) . They are competing to be the final entrant in a gay men 's chorus , and after learning that Owen is straight , Jack tries to " in " him with help from Grace ( Debra Messing ) . Meanwhile , Karen ( Megan Mullally ) tries to pass off Will ( Eric McCormack ) as her lover and not her lawyer when she discovers that she is the object of pity for being single at her own Valentine 's Day party . 
