How to find out if a movie star that isn't your friend is online

Ok, so I did this thing the other day. I was just messaging a famous movie star, when I pressed the button that shrinks the chat and it said #this movie star# has come online. I am not telling you who this is because I don't want any fights in the comments. The weird thing was this movie star (I wasn't friends with her) Popped up where my friends were on the bottom of the screen! LOL so thats how you find out a movie star is online even when your not friends with her/him