Witness: The Tour was the fourth concert tour by American singer Katy Perry, in support of her fifth studio album, Witness (2017). The tour began on September 19, 2017, in Montreal, Canada, and concluded on August 21, 2018, in Auckland, New Zealand. Perry visited North America, South America, Asia, Europe, Africa and Oceania. The tour ran for 7 legs and 115 shows, and it's supporting acts included musicians such as Noah Cyrus, Carly Rae Jepsen, Bebe Rexha, Zedd, and Hailee Steinfeld, alongside others.