Be weary next time you watch a review from your favourite YouTuber, as they might've been paid to say good things.

Warner Bros. has just reached a settlement with the Federal Trade Commission in the US over paying YouTube stars to give positive reviews to their video game Middle Earth: Shadow of Mordor.

No particular stars were named as having received payment, but PewDiePie, the video creator with the most subscribers on YouTube, was revealed to be one of them.

Tens of thousands of dollars was given to YouTubers, along with advanced copies of the game, to create videos giving the game positive feedback and encouraging people watching to buy it.

Warner Bros. also asked the YouTubers who made videos for them to bury the fact that the video was sponsored. Most of the videos did say they were sponsored, but it was hidden under the Show More tab of the description, where very few people tend to look.

The FTC ruled that Warner Bros. had deceived customers by paying for the positive reviews and asking for the sponsor message to be hid.

Videos related to the case had been viewed over 5 and a half million times, including 3.7 million views just from PewDiePie's video.