Did You Know That Luke and Leia Were Never Intended to Be Twins? Hence the kiss. In fact, at one time a sequel was planned where Luke would go in search of his long lost sister. In the end, however, George Lucas decided to resolve the issue in Return of the Jedi, and so made Leia his sister.
They Had Screaming Matches! Perhaps they aren’t really siblings but they certainly acted like it sometimes. Mark Hamill (Luke) says “Harrison and I never fought in either picture. It was Carrie (Leia) and I who had screaming matches from time to time, though afterward neither of us could remember what they were about.”