@QueenMia, I finished the Superstar event on the Holiday Calendar. I thought I was going to get a new costume for Olivia, but didn't. Did get some great boosters!
I completed all the weeks event without any failure and got two new costumes Santa Yeti n BGT Angel ( had other two already). In last week event I received 75 stickers of Olivia but a bit confused regarding unlocking the character. I dont know what should I do to get it.