After teasing it last year, YouTube has rolled out a new feature called Go Live Together that lets creators co-host livestreams. Anyone with over 50 subscribers can invite a guest to host a livestream with them from iOS and Android mobile devices. Only one guest is allowed at any time, but the host can swap in new guests during the same livestream.
You can schedule co-streams through YouTube's desktop app, but both the host and guest must use mobile devices during the livestream. To do so, open the YouTube app, tap "Create" then "Go Live Together." After entering stream details, select "Invite a co-streamer" and send an invite link to the co-streamer. They'll then be sent to the waiting room until you click "Go Live."
There's no minimum number of followers for guests, but the host will be held responsible for guests violating any community guidelines. Hosts can earn revenue for ads, which can appear in pre-, mid- and post-roll form.
YouTube offered a similar feature that lets creators co-host shopping livestreams, which allows both co-hosting and redirects to a brand's channel. Twitch recently introduced a feature in beta called Guest Star which allows creators to bring up to five guests onto streams. That system is a bit simpler, as any viewer can raise a virtual hand and the host can invite them on, much like Clubhouse or Twitter Spaces. Unlike YouTube's mobile limitation, Twitch's version is only available on desktop.