The UK Office of Fair Trading (OFT) has launched an investigation into celebrity product endorsements posted on micro-blogging platform Twitter.
The watchdog believes that the public are being deceived by Twitter users who don't disclose that an endorsement Tweet has been paid for.
The OFT said in a statement that undisclosed paid-for online endorsements were "deceptive" according to fair trading rules, adding that this includes "comments about services and products on blogs and micro-blogs such as Twitter."
This practice has come under scrutiny before in the US, where celebrities were instructed by the Federal Trade Commission (FTC) to declare when they are advertising a product by adding the words "ad" or "spon" to their tweets.
Celebrities like rapper Snoop Dogg can earn as much as $3,000 for sending out a tweet endorsing a particular brand, according to The Guardian.
The Guardian also reports the OFT has also brought a case against a PR firm for allegedly hiring bloggers to write about their clients. The OFT argues that such blogs and comments should inform users that they are paid for.