The two-and-a-half minute film shows office workers in costumes singing "I'm dreaming of an office party" to the tune of Bing Crosby's White Christmas.
It is the latest phase of Big Wednesday PR's Save the Office Party campaign.
Big Wednesday PR director Eugenie Tham said: "Our campaign has been aimed at office workers through various social media platforms and this is the highlight of the campaign. The video is a piece of festive fun to be passed around the office and encourage bosses to give their staff a little thank you for working so hard during such a difficult year."
She started the campaign after hearing how many companies were cancelling Christmas parties for employees and became concerned about its impact on the UK events industry.
The campaign's Twitter feed has gained more than 1,200 followers and Tham recently took industry leaders to meet BBC Radio 2 host Chris Evans.
- The video, produced in conjunction with Forcefed Media, can be viewed by visiting Save the Office Party on You Tube.