Pauley Perrette Pauley Perrette

Who is the real Abby Scuitto? We're about to find out when her brother comes to town.

After Abby volunteers to donate a kidney on Tuesday's NCIS, she learns a few shocking family secrets. "It affects Abby in a huge way," Pauley Perrette tells"It's a very, very big deal, and it will absolutely impact her for the rest of her life."

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Abby's brother, Kyle Davis, is played by Daniel Louis Rivas

, who is actually Perrette's ex-boyfriend. "I've been saying for years, ever since they mentioned Abby had a brother, that I know the actor that has to play it," Perrette says. "He was my boyfriend years ago, and we look so much alike. He has my same crazy eyes. People always thought that we were brother and sister. ... So, I started putting it on Twitter, and my followers started a huge Twitter campaign. And it worked!"That's not the episode's only real-life connection. The episode also features a locket that Abby carries with her. The woman pictured inside the locket is Perrette's mom, who died in 2002. Also like her character, Perrette is an advocate for many charitable causes (she's currently raising money for an annual AIDS Walk).So will it be another eight seasons before the show digs into Abby's backstory again? Executive producer Gary Glasberg says he's unsure if Abby's brother will make any return appearances, but he does suggest that the emotions this episode brings to the fore will likely be revisited later in the season. "A new world has opened up for her, and I hope that we'll have additional opportunity to help her figure that out," he says.NCIS airs Tuesdays at 8/7c on CBS.