I think I'm going to surprise you with my answer :)
Oona Chaplin (from Game of Thrones) is Charlie Chaplin's granddaughter!
Royally perfect! The Duchess of Cambridge is a distant cousin of the two famous sisters ( Elle and Dakota Fanning ). The trio are descendants of King Edward III.
Hugh Grant and Thomas Brodie-Sangster are cousins
Blake Lively's brother-in-law is Bart Johnson
Dakota Johnson's mother is Melanie Griffith, and her grandmother is Tippi Hedren.
Emily Deschanel and Zoey Deschanel are sisters
Rob Schneider's daughter is Elle King
Kesha has an IQ of 140 and scored 1500 on the SAT
Emily Blunt is Stanley Tucci's sister-in-law, which means that John Krasinski is Tucci's brother-in-law.
Jonah Hill is the older brother of the notable Lady Bird actress, Beanie Feldstein.