R2-D2 and C-3PO are two of the most iconic droids in the Star Wars universe. They are both astromech droids, with R2-D2 being a small, cylindrical DROID and C-3PO being a humanoid protocol DROID. Both droids have been featured in all nine of the main Star Wars films, as well as various other media. They are both loyal companions to the Skywalker family, and have been involved in many of the major events of the Star Wars saga.