Watch Olivia Rodrigo surprise trick-or-treaters for a Halloween 'Jimmy Kimmel Live' segment, which also features Kimmel's trusty sidekick Guillermo in an Olivia Rodrigo costume.

Olivia Rodrigo appeared on 'The Tonight Show Starring Jimmy Fallon' on Tuesday, Oct. 29, and spoke about her onstage fall in Melbourne, Australia, during her Guts World Tour earlier this month.