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Other household names who have pledged to the #HeForShe campaign include The Riot Club actor Douglas Booth, Joseph Gordon-Levitt, Sean Pegg and more.
Hiddleston's support came as it was revealed that the threat of a nude photo leak, thought to have been orchestrated by 4Chan hackers, might have been a hoax designed by a viral marketing company.
The site featured an image of Watson wiping a tear from her eye, as a digital timer counted down the seconds to the alleged leak.
However, when the timer got to the end, it redirected users to "campaign website" rantic.com, which claimed the leak had been a hoax designed to draw attention to the threat of 4chan to the internet.
"Dear humans, In the digital age we have a new kind of terror going on and it is called 4chan, Help us take down the terrorist group 4chan," Rantic tweeted, perhaps hoping that the media would cover the hoax as an anti-4chan campaign.
A spokesperson for Watson declined to comment on the report.
Many other male actors an celebrities have posted their support for Emma Watson and her #HeForShe campaign on twitter:
Harry Styles
Chris Colfer
Russell Crowe
Simon Pegg
Logan Lerman
Matthew Lewis (a.ka. Neville Longbottom)
- Independent
