Sex workers go to great efforts to hide their true identities from their clients – but Facebook’s People You May Know function might be putting their anonymity at risk.

One female sex worker from California was shocked to see some of her regular clients appearing on the feature when she was logged into her account, which is under her real name, Gizmodo reports.

“The worst nightmare of sex workers is to have your real name out there and Facebook connecting people like this is the harbinger of that nightmare,” she said.

“With all the precautions we take and the different phone numbers we use, why the f*** are they showing up?”

She told Gizmodo that her “real identity” – the one which is on Facebook – was created in 2011 and she uses it to post about politics.

Despite not revealing anything about her life as a sex worker on the social network, the People You May Know function was able to connect her to her clients.

Whilst for most people, the ambivalent feature may be no more than a vexing invasion of privacy, for porn stars and prostitutes it could be incredibly dangerous as it can reveal their true identities to clients and viewers, subsequently putting them at risk of stalking and blackmail.

Facebook has never disclosed the details of their “suggested friends” algorithm, though it’s assumed to work on the basis of mutual friends.

Leila – as she is named in Gizmodo’s article – believes that Facebook must have somehow accessed contact information from other apps on her phone or used location services to find that she was often in the same place as her clients.

However, a Facebook spokesperson told Gizmodo that they never use information from third party apps to gather their data, so it remains unclear how they were able to connect the supposed far-reaching dots between Leila and her clients on the site.

“We take privacy seriously and of course want to make sure people have a safe and positive experience on Facebook,” they said.