Katie Leung has only just started filming the fourth Harry Potter movie. But she's already proving a hit on the internet.
There are already dozens of websites dedicated to the 16-year-old who plays Cho Chang.
Most of these are fan sites, even though very little is known about the Scottish teenager. But there are also a few web logs who've been set up by people claiming to be Katie.
CBBC Newsround has been in touch with Katie's people at the studio, and they've confirmed that all of these web logs are fake. Katie has never had any kind of blog on the internet.
On the internet, you don't need Polyjuice Potion to pretend to be someone you're not. That means that it can be easy for people to fake their identity.
A few months ago, one fan travelled to England from abroad because she thought she'd been communicating with Dan Radcliffe over the internet. In fact, she'd been talking to a fake.
So if you think you've been reading a blog about what Katie's been up to or communicating with her, unfortunately the person you've been talking to is an imposter.
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