US comedian Sarah Silverman and two authors sued ChatGPT maker OpenAI and technology company Meta for allegedly infringing their copyright to train the companies' AI systems. 

The class-action case stated that copyrighted materials belonging to Silverman, Christopher Golden and Richard Kadrey, 'were ingested and used to train ChatGPT' by OpenAI without their permission.

The authors also claimed that 'many' of their books appeared in the Books3 dataset, which was used to train Meta's open-source LLaMA group of AI models in what the suit described as a 'flagrantly illegal' manner. 

The proposed class action asked for financial damages and 'permanent injunctive relief'. 

Lawyers are divided over whether the use of copyrighted books to train AI models constitutes legal 'fair use' under US law.