Jackson's father, Joe, was there, along with other members of his family. They cut the cake and fans danced to some of his greatest hits.
In honor of Jackson's birthday, Heal the World for Children is hosting a children's festival in Woodley Park in Van Nuys on Sunday.
In addition to food, entertainment and arts and crafts projects, there will be a children's moonwalk contest. The event will go from noon to 4 p.m.
Jackson died June 2009 of an overdose of sedatives.