A threat to actress Emma Watson on a website thought to have been set up by internet trolls behind the nude celebrity photo leak appears to have been revealed as a hoax, according to reports.

Earlier this week a web page entitled Emma You Are Next, featuring an image of the Harry Potter star next to a countdown clock, appeared to have been created by a user of image-sharing website 4chan, on which lewd photos of celebrities including actress Jennifer Lawrence and model Kate Upton were posted last month.

But now the website redirects to rantic.com, purporting to be a "social media marketing enterprise", with a message to United States president Barack Obama urging 4chan be shut down.

A message on the redirected site reads: "We have been hired by celebrity publicists to bring this disgusting issue to attention. The recent 4chan celebrity nude leaks in the past 2 months have been an invasion of privacy and is also clear indication that the internet NEEDS to be censored."