There's nothing like a good ol' fashioned 'video of a famous person surprising some kids' at this time of year to warm the ol' cockles.

This year, it's the turn of Justin Timberlake. The pop star dropped in on Newtown High School of Performing Arts in Sydney, Australia last month when he was in the country promoting Trolls.

Their music teacher had told them that a 'surprise guest' would be joining them to give them some feedback on their performances, although when he paused after 'Justin.....', there were no doubt some disappointed heads who expected the Biebs to make an appearance.

Nevertheless, Mr. JT came in, did the whole 'This is a treat for me' spiel and watched the teenagers strut their stuff while nodding in approval.

Watch it below: