That didn't take too long. After several weeks of testing, Instagram has given all mobile users the option to add a guest to their live broadcast. Tap an icon and you can invite one of your viewers to participate, splitting the view in two. You can swap guests at any time, and these group videos can either disappear right away or live a while longer as Stories in your friends' feeds. Friends can tell that it's a two-person stream with a quick glance at the Stories bar.