Star Wars The Force Awakens was an almost perfect way to bring the series back with big spectacle, plenty of entertaining moments and more than a few strong hits of nostalgia.
A big part of that appeal was the numerous appearances by familar characters including returning players like Harrison Ford and Carrie Fisher, as well as those metallic folks R2-D2 and C-3P0. This was a new movie though and 3P0 in particular looked different, sporting a new red arm.
Well the mystery behind that red arm has been teased ever since, with the answer said to be coming in a once off comic book that seemed to miss its release date multiple times over. It's finally out and you can get a breakdown of everything that happens in this video.
It sounds like a pretty great addition to the lore of Star Wars, and keeping the arm for the movie a fitting tribute to his time with a droid where he was treated as an equal for a change. If you notice in the finale of The Force Awakens, 3P0's arm is back to normal, so we wouldn't expect to see it pop up again in Episode 8.
The Force Awakens is on home video now, if you fancy a rewatch.