An insider tells PEOPLE that Jenner is "very upset" and supporting Guerrero's family "financially"Kylie Jenner is mourning the loss of a close friend.A source tells PEOPLE the mogul is "shocked" by the sudden death of her longtime hairstylist Jesus Guerrero.

Stars paid tribute to the hairstylist after he died "very suddenly and unexpectedly," according to his family.

Jesus Guerrero, a celebrity hairstylist who counted Kylie Jenner, Demi MOore and Jennifer Lopez among his clients, has died. He was 34.