The "One Love Manchester" benefit concert opened with a moment of silence for those affected by Saturday night's deadly terror attack in London.
Ariana Grande and other stars went on with the show just two weeks after a suicide bombing in Manchester.
Grande took the stage wearing a "One Love Manchester" sweatshirt and opened her performance with her song "Be Alright."
"I want to thank you so much for coming together, and for being so loving, and strong, and unified," Grande told the crowd.
The 23-year-old singer teared up when she spoke about meeting the mother of one of the Manchester bombing victims, 15-year-old Olivia Campbell.
“As soon as I met her I started crying and I gave her a big hug and she said I should stop crying because Olivia would have wanted me to stop crying,”
Grande said. “And she said Olivia would have wanted to hear the hits.”
All proceeds will go to the Red Cross's Manchester Emergency Fund.
Ariana Grande's benefit concert in Manchester, England, will continue tonight despite a deadly terror attack in London just a day prior,
Officials have said that security for tonight's concert, which features other stars besides Grande, will be heightened after a bombing at Grande's May 22 concert killed 22 and wounded more than 100 others.
"Today's One Love Manchester benefit concert will not only continue, but will do so with greater purpose," said Scooter Braun, Grande's manager, in a statement early Sunday. "We must not be afraid."
Grande will be joined onstage by other superstars such as Justin Bieber, Katy Perry, Miley Cyrus, Coldplay, Usher, Pharrell Williams, and the Black Eyed Peads.