https://www.pcgamer.com/fortnite-celebrity-pro-am-twitch-channel-breaks-700000-concurrent-viewers/

Fortnite continues to raise the bar for Twitch viewership, bringing in more than 700,000 viewers (and counting) to the official Fortnite Twitch channel during the first Fortnite Celebrity Pro-Am tournament. Recently, Ninja set a record with his strange, but entertaining Ninja Vegas event with an approximate 667,000 viewers. Other events have pulled in more on a single channel, but it's still huge.

A host of streamers were given permission to co-stream the even as well, bringing the total viewership on Twitch to 1.3 million. That doesn't even take into account the people watching on Twitter, YouTube, Facebook, and Mixer. All said, it might be one of the biggest live-streaming events ever.