Rachel Bilson and Hayden Christensen have been together since 2007 (to put that into perspective, that was the year Keeping Up With the Kardashians premiered), and the world has rarely gotten an inside glimpse at Their romance . . . until **w. Rachel, who recently joined Instagram, is starting to get the hang of the social media app and posted a cute photo on Friday of her and Hayden kissing in the summertime sunshine. Rachel captioned the photo with a simple heart emoji.