Lauren Graham and Peter Krause play brother and sister on NBC's Parenthood, but offscreen their connection is more intimate. The pair took a while to go public with their relationship, which they had kept secret for some time due in part to Graham's worries: "I've been really protective of it, because it's important that you can buy us as brother and sister on the show," she told Redbook. The couple has been a long time coming -- Graham and Krause first met 16 years ago when the actress moved to Los Angeles to begin her career. Sparks didn't exactly fly back then though. "He asked me over to his house to play a board game, and that's what we ended up doing," Graham admits. But now, a decade-and-a-half later, the costars are happily spending almost all of their time together, on set as siblings and off set as sweethearts!