The 60-second Fallon-created spot, set to an 1980s electro track called "Don't stop the rock" by Freestyle, opens with two siblings sitting in a traditional photographer's studio waiting to have their portrait taken.
When the photographer is called away by a ringing phone, the children break into a choreographed eyebrow dance. The ad breaks tonight live during the 'Celebrity Big Brother' finale on Channel 4.
Chris Willingham, a partner at Fallon said: "Like all good creative ideas nowadays, ‘Eyebrows' will entertain and spark conversation online and offline. It is designed to encourage involvement and imitation."
Phil Rumbol, marketing director for Cadbury, said: "'Eyebrows' marks our third original production following 'Gorilla' and 'Airport Truck' and we're confident it will prove just as popular and raise as many smiles -- but lots more eyebrows.
"Like the other productions, 'Eyebrows' is all about losing yourself and embracing that moment of joy -- except in this case there's a healthy dose of mischief mixed in too."
The confectionary giant said the ad will be supported by a number of activities throughout February and it is also offering consumers the chance to buy branded coffee mugs for £7.99.
Visitors to www.photobox.co.uk will be able to upload a photo of themselves or a friend and add some comedy eyebrows.