Home Alone fans have been left shocked after only just realising who the cop is at the beginning of the movie.

For those of you who haven't given it a re–watch this Christmas, during the opening scene of the flick we see a police officer visit the McCallisters’ home as the family get ready for their trip to Paris.

The cop then talks to patriarch Peter McCallister (played by John Heard) who lets him know about all the security measures he’s put in place ahead of their trip, in the wake of a spate of burglaries in the area.