FILE - In this Monday, June 12, 2017, file photo, Katy Perry performs during 'Katy Perry - Witness World Wide' exclusive YouTube Livestream Concert at Ramon C. Cortines School of Visual and Performing Arts in Los Angeles. The pop star’s “Witness: The Tour” is pushing back the start of her new tour to Sept. 19 in Montreal. Perry said in a statement Thursday, Aug. 17, that “major elements of my tour stage design could not be available for me to rehearse on until this week.” (Photo by John Salangsang/Invision/AP, File)
US singer Katy Perry, who is currently expecting her first child, will perform at Tomorrowland Around the World. AP

Katy Perry to perform at Tomorrowland online festival: 'I hope my set makes you smile'