Greta Thunberg has applied to trademark her own name and that of her Fridays for Future movement, according to an Instagram post from the 17-year-old.
The Swedish activist — who founded the global campaign that inspired thousands of students and adults to take part in weekly protests calling for swifter action to tackle climate change — said the trademark would stop "imposters" and would help in her launching her new non-profit foundation.
"Unfortunately there are still people who are trying to impersonate me or falsely claim that they 'represent' me in order to communicate with high-profile people, politicians, media, artists etc," she wrote.
"Please be aware that this is happening and be extremely suspicious if you are contacted by ”me” or someone saying they 'represent' me.
"I apologise to anyone who has been contacted — and even misled — by this kind of behaviour."
Speaking about the trademarks, she added: "This action is to protect the movement and its activities.
"It is also needed to enable my pro bono legal help to take necessary action against people or corporations etc who are trying to use me and the movement in purposes not in line with what the movement stands for.
"I assure you, I and the other school strikers have absolutely no interests in trademarks. But, unfortunately, it needs to be done.
"Fridays For Future is a global movement founded by me. It belongs to anyone taking part in it, above all the young people. It can - and must - not be used for individual or commercial purposes."
The teenager went on to say she had also begun setting up a not-for-profit foundation to handle money she receives from book royalties, donations and prize money "in a completely transparent way".
She added: "The foundation’s aim will be to promote ecological, climatic and social sustainability as well as mental health."
- Prince Charles to tell Davos sustainability should be 'cheaper'
- Donald Trump and Greta Thunberg clash on climate at World Economic Forum
- Greta Thunberg brushes off Mnuchin barb she should study economics
The post came just over a week after Thunberg made an appearance at the World Economic Forum, where she warned that "inaction was fuel to the flames of climate change".
At the event, she also made an impression on Prince Charles, who went on to say the 17-year-old was "remarkable".
He said: "She represents one of the main reasons why I've been trying to make all this effort all these years because, as I said, I didn't want my grandchildren to accuse me of not doing something about this in time and of course there they are."