Elijah Wood and Macaulay Culkin 

These two child stars became friends in the 1990s. In response to a tweet questioning whether the two were genuine friends, Macaulay Culkin wrote: "Of course we're friends. @elijahwood and I will always be brothers ... until he inevitably drops me off a cliff. #SpoilerAlert." The falling off the cliff thing is a reference to the 1993 film, 'The Good Son', which they both starred in.