Brand owners and their attorneys are grappling with an important question: how to disclose their connections to luminaries like PewDiePie.

If you haven’t heard of PewDiePie, don’t worry—he’s a 26-year-old Swedish college dropout who likes to sit at his computer, play video games and shoot movie clips. But he also happens to operate the most popular YouTube channel in the world. He has nearly 50 million subscribers, and his commentary wields huge influence over the success of a video game release. Marketers pay him to exercise it. Last year, PewDiePie’s production company reported an operating profit of about $8.1 million.