Young fans and their families were expected to dominate the audience at the Ariana Grande concert in Manchester Arena where a suspected terror attack killed at least 19 and injured dozens more.
The 23-year-old US pop singer, who found fame as the child star of Nickelodeon series Victorious, was touring the world when tragedy struck on Monday night.
Associated acts such as Katy Perry, Nicki Minaj and Taylor Swift tweeted their support for fans of Grande.
The Dangerous Woman Tour started in Phoenix, Arizona, on February 3 and she was joined by British pop stars Little Mix during a spell in the US.
She then made stops in Dublin, Sweden, Norway, Denmark and the Netherlands.
After Manchester she was due to play two nights in London's O2 Arena before visiting Poland, Germany, Switzerland, France, Spain and Italy.
The Floridian was also scheduled to visit Mexico, Brazil, Japan, Thailand and Australia before bringing the tour to a close in Hong Kong in September.
A representative from Grande's US record label, Joseph Carozza, said the singer was okay.
BIA, also known as Perico Princess, was a supporting act on the night of the explosion in Manchester.
She tweeted: "My heart is broken. Praying for everyone tonight please gets home safe."