If you see a message on Facebook, apparently coming from one of your friends, and promising a link to the 'sexiest video ever' then whatever you do, don't click on it. The video link messages promise a 'candid camera prank' seemingly involving a woman in a short skirt riding an exercise bicycle, but according to security experts at Sophos actually delivers a malicious payload via a rogue Facebook application instead.

Like so many scams of the type, this one will inform any Facebook who does click on the link that they need to install specific video player software to view the video. The payload being a double whammy of adware and the posting to all Facebook friends of copies of the same message that made the victim click the link in the first place.

"You may want to watch a sexy video, but you're more likely to end up being plagued by pop-up advertising" warned Graham Cluley, senior technology consultant at Sophos who adds "it's no surprise that your friends might click to watch the movie when it looks to all intents and purposes that you are the person who has sent it to them."

Sophos advises Facebook users who are worried they may have already clicked on this video link, and it appears victims could number in the thousands, to change passwords remove whatever Facebook application was installed as a result of the scam. Oh, and to scan their computers with up to date anti-virus software to be on the safe side.