diff --git a/src/packages/collaboration/lib/guest-session.coffee b/src/packages/collaboration/lib/guest-session.coffee
index 5148e9e92..c97bcb746 100644
--- a/src/packages/collaboration/lib/guest-session.coffee
+++ b/src/packages/collaboration/lib/guest-session.coffee
@@ -19,6 +19,8 @@ class GuestSession
         doc = telepath.Document.deserialize(data, site: telepath.createSite(@getId()))
         atom.windowState = doc.get('windowState')
         @participants = doc.get('participants')
+        @participants.on 'changed', =>
+          @trigger 'participants-changed', @participants.toObject()
         connectDocument(doc, connection)
 
         @trigger 'started'