Grande - who finished the show by singing Somewhere Over the Rainbow before breaking down in tears - claimed she was inspired to change her set list after the mother of teenage victim Olivia Campbell, 15, said her daughter would have wanted "to hear the hits". She was joined by several other artists and celebrities. By far the best vocal performance tonight.
"I had the pleasure of meeting Olivia's mummy a few days ago and I started to cry and gave her a big hug and she said "stop crying, because Olivia wouldn't have wanted you to cry", she told the crowd.
The gig marked Grande's first performance since bomber Salman Abedi detonated a bomb, killing her fans and parents as they left her show at Manchester Arena. The 50,000-strong crowd emotionally sang along and waved their lit-up phones as they mouthed the song's powerful lyrics.
Talk Radio host Julia Hartley-Brewer definitely struck the wrong note when she tweeted: "Why does anyone in their right minds think Islamic terrorists care one iota about a copper dancing with some kids at a pop concert?"
Ariana was joined by Black Eyed Peas, Robbie Williams, Take That, Justin Bieber, Coldplay, Niall Horan, Miley Cyrus, Katy Perry, Pharrell Williams, and Little Mix at the event, where fans were also treated to a surprise appearance from Manchester's own Liam Gallagher.
Grande's hit One Last Time has been re-released as a charity single, with proceeds going to the campaign.
The benefit concert raised £2.35 million for the UK Red Cross.