Reese Witherspoon grooved to the music from her Skullcandy headphones while filming This Means War in Vancouver yesterday. Reese is back up North after a quick trip home to LA to visit Jim Toth and her kids over the weekend. She's been showing off her toned legs with short skirts on set recently, though this time she was covered up in casual sweats to film without costars Chris Pine or Tom Hardy. The trio will soon become a foursome when their new costar Chelsea Handler joins the cast as Reese's best friend.