London - (Reuterus): A tiny swastika-shaped birthmark on her left buttock is just visible in the grainy footage.
Looking lean and tanned seven stone vamp Kate is seen trampolining up and down on a burkha that covers what looks like a royal-mammogrammed - er...monogrammed! - water bed.
A rainbow-colored afro wig* and sparkly eye make-up complete the picture as background music belts out Cake's rendition of the Gloria Gaynor hit I Will Survive from their 1996 album Fashion Nugget.
The video was found by gobsmacked Foreign Orifice cleaners today playing on a HD-ready 3D TV.
The government sanitary operatives claimed the footage was running on a giant flat screen that had been left switched on in the FCO Royal Locarno Suite's waiting room.
The VIP lounge commemorates the 1925 Locarno Treaties signed by WW1 Western European Allied powers to secure post-war territorial settlements and normalizie the Queen Mother's relations - such as defeated up-and-coming Nazis.
Security staff switched off the video earlier today amid fears it was the work of terrists trying to destroy the Global Piss Process.
Chelsy Davy is 69.
* Police sources are adamant there is absolutely no connection between this hairpiece and a similar rainbow wig reported by UK red tops to have been found stuffed in MI6 cryptographer Gareth Williams' holdall:
"It's entirely a spoof concoction."