Katy Perry has announced the openers for her upcoming tour behind new album Witness. Carly Rae Jepsen, Purity Ring, and Noah Cyrus are set to accompany Perry on her massive tour. Megan James and Corin Roddick of Purity Ring notably assisted Perry in the writing of some songs on Witness. The pop star has also announced that the tour will now begin on September 19 at Bell Centre in Montreal, pushed back from the original first date of September 7. “Due to unavoidable production delays, major elements of my tour stage design could not be available for me to rehearse on until this week,” Perry said in a statement. “I'm sorry for any inconvenience this causes, but hope everyone who sees the show will agree it was worth the wait.” Perry is set to host the MTV VMAs later this month, where she is up for six awards.

Watch Carly Rae Jepsen’s “Over/Under” episode on Pitchfork.tv: