Sir David Attenborough has revealed internet trolls have been impersonating him on social media and sending his fans "obscene" messages.
The 87-year-old broadcaster said that at least two bogus profiles have been set up in his name and messages claiming to be from him had been sent to different social media users.
"They're horrible, rude - er, sexy rude - so you have to get a lawyer to take them down," he told The Sun.
"If you get a lewd message, it's not from me."
Sir David said he does not use email and has never had social networking accounts, so he was surprised to hear that people were using fake accounts under his name.
He has since instructed his lawyers to act so as to protect his reputation by requesting the removal of an account from Twitter and one from Facebook.
The national treasure spoke after finishing filming for a second series of David Attenborough's Natural Curiosities, which will air in February 2014.