Jonathan Ross has inadvertently highlighted to Twitter users that deleting a post from the micro-blogging service doesn't actually remove it completely.
Ross, who has more than a quarter of a million Twitter followers, posted his full email address but then quickly deleted the message, after realising his error.
However, by using Twitter's Advanced search facility, all posts (whether they have been deleted or not) can be found, meaning that thousands of Twitter users can still get hold of Ross's personal email address.
Graham Cluley, senior technology consultant at security firm Sophos, called Twitter "irresponsible" for failing to delete posts completely.
"In Ross's case, his email address could have been scooped by spammers or used by fraudsters pretending to be the star," said Cluely.
Cluely added that all Twitter users could type something they didn't mean to, or post the message in public rather than send as a direct mail.
"Accidents like this will happen, and Twitter should be helping, not hindering, its users to clean up the mess afterwards. For Ross, his best bet is to change his email address as soon as possible."