hanger on

/ˈhæŋər ˌɑn/
noun
  1. A person who associates with a wealthy or famous person in the hope of gaining some advantage, without being a true friend or member of the group.
    • The band's tour bus was full of hangers-on who didn't help with any work.
    • The celebrity was surrounded by hangers-on who only wanted his money.
    • She grew tired of the hangers-on who never offered genuine support.