The shocking advert, which appeared on Wednesday, invites fans to turn up in the terrifying costumes on Saturday night.
But the advert from the flagship Leicester Square branch of the fast food restaurant has prompted further fears that the terrifying 'killer clown' craze will return.
Posters advertising the burger featured a clown eerily similar to murderous, blood-thirsty clown Pennywise from Stephen King's IT.
The horrific clown craze swept across Britain last year, with hoards of parents and children being forced to flee menacing teens in the outfits.
*WARNING* if you have a clown phobia - don't watch the following video
The first person in British legal history was prosecuted for scaring kids last October as cops fought to stamp out the trend.
Officers at Thames Valley Police revealed they were called to 14 killer clown pranks in less than 24 hours in one weekend before Halloween 2016.
A young mum in Derby ran for her life in March after a clown jumped out on her armed with a chainsaw.
At the time, a Derbyshire Police spokesman said: "We received a report from a woman who was walking with her young child when a man dressed in a clown outfit jumped out at her, holding what appeared to be a chainsaw.
"We're investigating the circumstances of that incident and want to hear from anyone who knows who was responsible for it.
"It's not an offence to dress up as a clown but you might be breaking the law if you act in a menacing or threatening manner towards somebody else, particularly if you brandish an item such as a chainsaw.
"Last year, there were a number of incidents where people were seen dressed as clowns, and constant media and social media coverage seemed to encourage others to do it too.
"Anyone who is thinking of dressing up as a clown to go out and scare people needs to consider how their actions could affect others.
"Incidents involving clowns that are causing alarm or distress to members of the public will be taken seriously by the police.
"It might seem like a harmless prank, but some people have genuine fears and subjecting someone to a terrifying experience - even if it is funny to you - is simply not acceptable, and we will take action where appropriate."
Burger King have been contacted for a comment.