Elon Musk is suing OpenAI, the makers of ChatGPT, arguing it has breached the principles he agreed to when he helped found it in 2015.
The lawsuit - which has also been filed against OpenAI boss Sam Altman - said the firm has departed from its original non-profit, open source mission.
It said instead of trying to "benefit humanity" - as it was set up to do - it is focusing on "maximising profits" for major investor Microsoft.
OpenAI has been approached for comment.