(CNN) Ariana Grande performed before a jubilant crowd of some 50,000 in Manchester on Sunday, less than 24 hours after a deadly terror attack in the heart of London.

"I want to thank you from the bottom of my heart for being here today," the singer said between songs. "I want to thank you so much for coming together and being so loving and strong and unified. I love you guys so much and I think that the kind of love and unity you're displaying is the kind of medicine that the world really needs right now."

The "One Love Manchester" benefit concert by Grande and other pop stars went on as planned in the UK city, which is still recovering from a suicide bombing at Grande's show there two weeks ago.

Officials said security was bolstered for the concert, which aims to raise money for those affected by the bombing that killed 22 people and wounded more than 100 at Grande's May 22 show.

A post shared by Luis Antonio Cabrera (@luisantcab21) on Jun 4, 2017 at 11:44am PDT

'Choose love'

The show opened with a minute of silence for those killed and injured in the attack.

Then the crowd danced and sang through an all-star line up, which included Justin Bieber, Katy Perry, Miley Cyrus, Coldplay, Pharrell Williams, Usher and the Black Eyed Peas.

Perry urged the crowd to "choose love."

"It's not easy to always choose love, is it?" she asked the crowd. "Especially in moments like these, right? It can be the most difficult thing to do. But love conquers fear and love conquers hate," she said. "I encourage you to choose love, even when it's difficult. Let no one take that away from you."

What an event! #manchester #onelovemanchester A post shared by Lawrence Jones MBE (@lawrencejonesmbe) on Jun 4, 2017 at 11:42am PDT

The sentiment was echoed by fellow pop star, Justin Bieber, who said "You guys are so brave. ... Would you agree that love always wins?"

Grande ruled the night, performing her own songs and then joining the band Coldplay to perform the song "Don't Look Back in Anger." The song, written by Manchester band Oasis in 1995, has become a symbol of the city's resilience in the face of tragedy.

#Manchester #onelove #love #bestrong A post shared by Paul Brierley (@biggles1508) on Jun 4, 2017 at 12:35pm PDT

Last week, locals spontaneously broke into a rendition of the song at a public memorial to the victims of the attack.

The lead singer of Oasis made a suprise appearance during Coldplay's set. Hometown hero Liam Gallagher joined the band to sing "Live Forever," which he dedicated to victims of the attack.

Grande closed the show with a soaring rendition of "Somewhere Over the Rainbow," from the classic 1939 film, "The Wizard of Oz."

'Determined to carry on'

Some fans questioned whether Sunday's show would go on after three men drove a van into a crowd on a London bridge Saturday night before leaping out and stabbing numerous people in nearby bars and restaurants. Seven people were killed and 48 injured in the attack.

Photos: One Love Manchester Concert Ariana Grande performs during 2017's One Love Manchester Benefit Concert at Old Trafford on Sunday, June 4, in Manchester, England. The benefit concert by Grande and other pop stars went on as planned in the UK city, which was the site of a suicide bombing at Grande's show two weeks earlier. Hide Caption 1 of 20 Photos: One Love Manchester Concert A music fan hugs a police officer as fans leave Old Trafford Cricket Ground after the benefit concert for the families of the victims of the May 22, 2017 Manchester terror attack. Hide Caption 2 of 20 Photos: One Love Manchester Concert A fan high-fives a police officer as fans leave the concert. Hide Caption 3 of 20 Photos: One Love Manchester Concert People leave the stadium after the concert. Hide Caption 4 of 20 Photos: One Love Manchester Concert Ariana Grande performs with The Children's Choir. Hide Caption 5 of 20 Photos: One Love Manchester Concert Katy Perry performs. Hide Caption 6 of 20 Photos: One Love Manchester Concert Ariana Grande and Miley Cyrus sing a duet. Hide Caption 7 of 20 Photos: One Love Manchester Concert Miley Cyrus performs at the benefit with Pharrell Williams. Hide Caption 8 of 20 Photos: One Love Manchester Concert Marcus Mumford performs. Hide Caption 9 of 20 Photos: One Love Manchester Concert A view of the crowd in a handout photo provided by the concert's organizers. Hide Caption 10 of 20 Photos: One Love Manchester Concert Grande performed before a jubilant and defiant crowd in Manchester less than 24 hours after another deadly terror attack which occurred in the heart of London. Hide Caption 11 of 20 Photos: One Love Manchester Concert "Our response to this violence must be to come closer together, to help each other, to love more, to sing louder and to live more kindly and generously than we did before," Grande said. Hide Caption 12 of 20 Photos: One Love Manchester Concert Fans at the concert. Hide Caption 13 of 20 Photos: One Love Manchester Concert Officials say security was bolstered for the concert, which aims to raise money for those affected by the bombing that killed 22 people and wounded more than 100 at Grande's May 22, 2017 show. Hide Caption 14 of 20 Photos: One Love Manchester Concert A strong police presence is seen outside the event. Hide Caption 15 of 20 Photos: One Love Manchester Concert A litany of stars signed on for the benefit, including Justin Bieber, Katy Perry, Miley Cyrus, Coldplay, Pharrell Williams, Usher and the Black Eyed Peas.

Hide Caption 16 of 20 Photos: One Love Manchester Concert Manchester authorities warned that everyone going to the concert would be searched, and the presence of armed police would be visible inside and outside the venue.

Hide Caption 17 of 20 Photos: One Love Manchester Concert Members of the public are searched ahead of the concert. Hide Caption 18 of 20 Photos: One Love Manchester Concert Members of the public arrive before the concert. Hide Caption 19 of 20 Photos: One Love Manchester Concert Fans are given "We Stand Together" stickers as they arrive at the concert. Hide Caption 20 of 20

Grande's management answered doubts on Twitter, just hours before the concert.

"All artists involved have been unwavering in their support this morning and are determined to carry on with the show. We ask the strong city of Manchester and the world to join us in making the statement that hatred and fear will never win," Braun said.

He went on to encourage fans to keep their concert plans, "and in tribute to all those affected here and around the world, we will bring our voices together and sing loudly,"

As details emerged of Saturday's terror incident, Grande responded with a tweet: "Praying for London."

Praying for London ♡ — Ariana Grande (@ArianaGrande) June 4, 2017

As of late Sunday morning few of the other performers had tweeted in response to the London attack. But all had stated their commitment to the benefit concert in the week leading up to the show.

The music community stands together with love and in solidarity. I am humbled to be a part of this show ❤️🇬🇧 pic.twitter.com/7nqYBCJK4P — KATY PERRY (@katyperry) May 30, 2017

"Despite all the things that have been going on...I don't feel or smell or hear or see any fear in this building," Pharrell Williams said while singing a duet of "Happy" with Miley Cyrus.

Heightened security

Manchester authorities warned that everyone going to the concert would be searched, and the presence of armed police would be visible inside and outside the venue.

The Greater Manchester Police said more than 130,000 people were expected in the area for the benefit concert as well as a soccer match.

"There are two large-scale events taking place in Greater Manchester today and we would like to assure people that these will still take place, but with additional security in place to ensure the safety of everyone," Greater Manchester Police Assistant Chief Constable Garry Shewan said in a statement on Sunday.

Grande's concert was held at Emirates Old Trafford, an outdoor stadium about 3.5 miles from Manchester Arena, where the May 22 concert took place.

Fans were alerted that security at the show would be tight.

Greater Manchester Police Chief Superintendent Stuart Ellison said there would be a "significant number of officers" at the venue and encouraged people to leave bags at home.

If you're attending a concert this weekend. Follow this safety advice. https://t.co/uQerwpMgI2 — G M Police (@gmpolice) June 4, 2017

Fans still hospitalized

Grande surprised young fans injured in last month's attack with a visit to the Royal Manchester Children's Hospital on Friday.

The singer shared a photo to Instagram of herself meeting with a young girl, Jaden Mann.

💛 A post shared by Ariana Grande (@arianagrande) on Jun 2, 2017 at 4:48pm PDT

Jaden also shared pictures of the pop star at her bedside.

I got to meet my queen today❤❤love you @ArianaGrande💖💖xxxxxx pic.twitter.com/xTymQaRoN2 — jaden farrell mann (@dustyblu10) June 2, 2017

"Ariana brought everyone a sunflower and a teddy bear," Lauren Thorpe told CNN. "It was unbelievable."

Thorpe's eight-year-old daughter, Lily, suffered a shrapnel wound in her back and is recovering from surgery.

JUST WATCHED Grande visits victims at Manchester hospital Replay More Videos ... MUST WATCH Grande visits victims at Manchester hospital 00:58

Also on Friday, Grande met privately with some of those who lost loved ones in the May 22 attack, including parents of Martyn Hett, 29, and Courtney Boyle, 19.

'Music will heal us'

Grande canceled upcoming shows in London and Switzerland to prepare for Sunday's "One Love Manchester" concert.

She had just left the stage May 22 when a suicide bomber detonated a nail bomb outside the arena as people were streaming out of the venue.

Photos: Deadly explosion at Ariana Grande concert Photos: Deadly explosion at Ariana Grande concert People in Manchester, England, gather in St. Ann's Square on Thursday, May 25. They were observing a national minute of silence to remember the victims of a suicide bombing at an Ariana Grande concert. Hide Caption 1 of 22 Photos: Deadly explosion at Ariana Grande concert Britain's Queen Elizabeth II speaks to 15-year-old Millie Robson and her mother, Marie, during a visit to the Royal Manchester Children's Hospital on May 25. The Queen was visiting those injured in the attack. Hide Caption 2 of 22 Photos: Deadly explosion at Ariana Grande concert A police officer guards a house in Manchester as investigations continued on May 25. Police say a man carrying explosives acted as a lone attacker and died in the blast. Hide Caption 3 of 22 Photos: Deadly explosion at Ariana Grande concert Flowers and tribute messages are left for victims in St. Ann's Square. Hide Caption 4 of 22 Photos: Deadly explosion at Ariana Grande concert A women sheds tears after observing the minute of silence in St. Ann's Square. Hide Caption 5 of 22 Photos: Deadly explosion at Ariana Grande concert A Manchester road is closed off as police raids continued on May 25. Hide Caption 6 of 22 Photos: Deadly explosion at Ariana Grande concert Local residents hold Manchester City and Manchester United soccer jerseys during the national minute of silence. Hide Caption 7 of 22 Photos: Deadly explosion at Ariana Grande concert Police officers deliver flowers to a makeshift memorial in Manchester on Wednesday, May 24. Hide Caption 8 of 22 Photos: Deadly explosion at Ariana Grande concert Women cry after placing flowers in Manchester on May 24. Hide Caption 9 of 22 Photos: Deadly explosion at Ariana Grande concert A forensics team works at the scene of the explosion on Tuesday, May 23. Hide Caption 10 of 22 Photos: Deadly explosion at Ariana Grande concert British Prime Minister Theresa May condemns the "callous terrorist attack" as she delivers a statement in London on May 23. Hide Caption 11 of 22 Photos: Deadly explosion at Ariana Grande concert Police help someone after the attack at Manchester Arena on Monday, May 22. Hide Caption 12 of 22 Photos: Deadly explosion at Ariana Grande concert People gather outside the arena. "We can confirm there was an incident as people were leaving the Ariana Grande show last night," police said on Twitter early on Tuesday. "The incident took place outside the venue in a public space. Our thoughts and prayers go out to the victims." Hide Caption 13 of 22 Photos: Deadly explosion at Ariana Grande concert People receive medical attention at a railway station close to the arena. The incident happened shortly after Grande had left the stage, shortly after 10:30 p.m. (5:30 p.m. ET) according to eyewitnesses. Calvin Welsford, an 18-year-old concertgoer, said that he heard a "loud bang" a couple of minutes after Grande's set had finished. Hide Caption 14 of 22 Photos: Deadly explosion at Ariana Grande concert Paramedics respond to the scene. Hide Caption 15 of 22 Photos: Deadly explosion at Ariana Grande concert Emergency workers and concert attendees gather outside the arena. Hide Caption 16 of 22 Photos: Deadly explosion at Ariana Grande concert People stand by a cordoned-off street close to the arena. Hide Caption 17 of 22 Photos: Deadly explosion at Ariana Grande concert Greater Manchester Police tweeted that emergency services were "responding to (a) serious incident at Manchester Arena. Avoid the area. More details will follow as soon as available." Hide Caption 18 of 22 Photos: Deadly explosion at Ariana Grande concert People are escorted away from the arena. Hide Caption 19 of 22 Photos: Deadly explosion at Ariana Grande concert People sit outside near the arena. The crowd was made up of mainly younger people who had come to see Grande in her first of three scheduled concerts in the UK. Hide Caption 20 of 22 Photos: Deadly explosion at Ariana Grande concert An injured man is helped at the scene. Hide Caption 21 of 22 Photos: Deadly explosion at Ariana Grande concert People hug near armed police who responded to the scene. Hide Caption 22 of 22

Within days, the singer posted a message of defiance and announced plans to return to Manchester for the benefit show.

"Our response to this violence must be to come closer together, to help each other, to love more, to sing louder and to live more kindly and generously than we did before," Grande said. "Music is meant to heal us, to bring us together, to make us happy. So that is what it will continue to do for us."