A hidden search feature turns smartphones into mobile Christmas caroling karaoke machines.
Every year Google stashes an Easter egg in one of its services as a yuletide treat and 2013 is no exception. However, it is confined to mobile devices.
To unlock the feature and enjoy some spontaneous Christmas fun, simply Google the term "let's go caroling" on any Apple or Android phone or tablet and a list of five classic Christmas Carols will appear.
Wannabe carollers can pick from "Jingle Bells," "Up on the House Top," "Deck the Halls," "O Christmas Tree" and "We Wish You a Merry Christmas."
Click on one of the titles and the backing music will start and the lyrics will appear on-screen, in time with the music. The song can be skipped forward and backwards and paused too, for added control.
Also in keeping with tradition, Google's latest Easter Egg will not work on Windows Phones. Bah Humbug.