Ruby is Poppy's ex-bestfriend. Ruby is portrayed by Shelby Young.
Ruby is a shallow, spoiled, and mean-spirited girl who (similar to how Poppy was in the beginning) has a spoiled attitude. Unlike Poppy, she is also completely disloyal and unfaithful; she clearly only cares about Poppy’s money rather than Poppy herself as a person, and is not above sleeping with another girl’s boyfriend.
Biography (in Wild Child)
Ruby appears at the beginning of the movie where Poppy plays a mean-spirited prank on her dad's girlfriend by having her friends trash her dad's girlfriend's stuff. As punishment, Mr. Moore has Poppy sent off to Abbey Mount, an all-girls boarding school all the way over in England. Ruby helps Poppy pack up her things and ends up keeping a pair of Poppy's shoes, showing distaste for Poppy’s little sister. A little while after transferring to Abbey Mount, Poppy tries calling Ruby to tell her what's going on at her new school, but Ruby ignores it and it turns out that Ruby has been hooking up with Poppy's boyfriend, Roddy.
After Poppy gets into trouble with her friends and Freddie Kingsley (the son of Abbey Mount's headmistress), Poppy calls Ruby again, but not only does Poppy learn how much Ruby dislikes her, she also learns that Ruby and Roddy have been dating behind her back for the entire time that she's been in England.
Poppy eventually patches things up with her friends at Abbey Mount as well as Freddie, who ultimately becomes her boyfriend. While Poppy’s relaxing in Malibu with Freddie and her Abbey Mount-BFFs, Ruby tries calling Poppy, but after realizing what Ruby’s really like, Poppy just ignores her. What happens to her is unknown afterwards, but it is most likely that Ruby is no longer considered Poppy’s friend.