Prime Minister David Cameron has started following a high-class escort agency on Twitter.
Carltons of London's website said it offered the "finest London escorts to gentlemen of distinction".
Number 10 did not offer the BBC an explanation as to why the PM's official account - which is run by a team - is following the agency.
It is the latest embarrassing social media incident that has involved Mr Cameron in recent weeks.
Last month an offensive tweet about foreign secretary William Hague was accidentally "favourited".
That instance was blamed on a mistake made by one of Mr Cameron's aides responsible for helping to run the account.
In this latest incident, Carltons of London has managed to attract the prime minister's attention - despite only ever posting two tweets.
One post reads: "We are London's finest luxury boutique escort service and provide London's most stunning escorts for every occasion."
The BBC could not reach the agency on Wednesday.
However technology news site The Register - which first reported the apparent slip-up - quoted a source at the agency as saying: "I don't know anything about the Prime Minister or Twitter."
The site speculated that the Prime Minister - or more likely, an aide - might have been looking for the Carlton Club, a private members club for supporters of the Conservative Party.
James Potter