ET was there as Reese Witherspoon premiered her festive holiday flick 'Four Christmases' at Grauman's Chinese Theatre in L.A. Thursday night. Watch her co-stars share what it was like to work with the actress, and hear Reese talk about some minor problems she had while filming scenes with Vince Vaughn! "I was always on a ramp or a box or something," Reese tells us about shooting scenes with Vince. "It was difficult during the kissing scenes trying to reach up that high." Other stars from the film on hand included Robert Duvall, Mary Steenburgen, Sissy Spacek and Kristin Chenoweth.