Well it looks like Apple are joining in on the Christmas adverts this year! They have combined miniature sets, made the same way Stop-Motion films are made, but chosen to add the characters in CGI. The process looks quite incredible. They use real time camera moves and lights etc to film the shot without any characters. Very similar to making a first pass if you were looking at deleting rigging out of a complex shot.
Only once they have there shot they track the camera using points on the set to determine the cameras depth of field etc. Bring all of the tracking coordinates into a CGI program... probably Maya and added the CG characters into the world. It's very clever and gives a real unique look to the advert. See for yourself below.
Behind the scenes
Let me know what you think