From Gabourey Sidibe's phone-sex operating past to Christopher Walken's stint as a lion timer, see the craziest things stars have done before making it big.
James Corden's Carpool Karaoke has taken the world by storm, and this year for Christmas he recruited Mariah Carey and a whole host of celebs to help sing her 1994 hit "All I Want for Christmas is You." But do you recall 2015's Christmas tune in the car?