Gyllenhaal's legal team has fired off letters to a number of websites, including Queerty.com and Buzzfeed.com, demanding that the photo is removed.

The star's attorneys write, "As anybody could tell from a cursory examination, this is a fake picture, in which our client's head has been pasted on the body of another person", adding that it portrays him "in a false light, violating his right of publicity and constituting a false designation of origin in violation of the Lanham Act".

But Gyllenhaal has a fight on his hands - chiefs at Queerty.com are refusing to remove the image until it is proved to be a fake: "We're keeping the photo up, since it hasn't been proven fake and because their letter bumped it from 'funny and cute' to 'actually newsworthy.'"