In a GQ interview leading up to The Last Jedi there was this delightful excerpt:
Other times, Driver playfully embraces the absurdity of it all. "I can't say anything, but what if I signal you," he jokes. "If I just start sneezing uncontrollably..." He fakes a loud achoo and exclaims, "Bingo! Harrison Ford's ghost returns!"
Damn how I wish this was a filmed interview.