Rachel Bilson and Hayden Christensen had a laugh over lunch today in LA, as they grabbed a casual bite from a food truck. They're back in LA following a romantic getaway to the Caribbean late last month. Rachel Bilson wore a bikini during their Barbados vacation, which came hot on the heels of the couple's trip to NYC. Hayden was by Rachel's side as she headed east to debut Karl Lagerfeld-directed Magnum ice cream ads at the Tribeca Film Festival. They took advantage of their opportunity to spend some time beachside and in the Big Apple before Rachel gets back to work this Fall. Her new TV show, Hart of Dixie, will debut on the CW, and she got a head start promoting the fish-out-of-water series with her network costars at the upfronts last week.