PHOTOS: Ariana Grande and others spread the love during One Love Manchester concert

MANCHESTER -- Less than two weeks after 22 people died in a terror attack at an Ariana Grande concert, the singer returned to the city of Manchester to perform in front of 50,000 people in an emotional concert benefitting the victims.

Grande performed many of her hit songs. Artists like Justin Bieber, the Black Eyed Peas and Miley Cyrus also performed. Grande said she completely changed the tone of the concert after meeting with the family of 15-year-old Olivia Campbell, one of the victims who died.

"Olivia would've wanted to hear the hits [today,]" Grande told the crowd. "We had a totally different show planed. We changed everything."

Grande performed "Break Free," "One Last Time," and more of her songs, also joining the Black Eyed Peas onstage for their song "Where is the Love?" and singing a duet of "Don't Dream It's Over" with Cyrus.

More than $13 million had been raised by Sunday night for the We Love Manchester Emergency Fund, the British Red Cross told the Associated Press.

For more information on donating, visit onelovemanchester.com or donate on Facebook.

If you make donations, please note that donations go to the UK Red Cross and may not be tax deductible. Additional fees may also apply.

ABC News contributed to this report.