Wow! This is a Christmas episode that see the Deschanel sisters sharing the screen! Even if you’re not a fan of the show, this is a must-see just for the novelty of it.
Never realised how petite Zooey is compared to Emily. 
Here’s what E! Online has to say about it : http://www.eonline.com/uberblog/b157430_what_does_zooey_deschanels_guest_gig_on.html