Justin Bieber, Coldplay, Katy Perry, Miley Cyrus, Pharrell Williams, Usher and Take That will join her for Sunday's concert in memory of the 22 people who died, seven of them children.
"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.
The 23-year-old said she was "broken" and suspended her world tour after the bomb went off near an exit of the Manchester Arena venue at the finale of her show on May 22.
Fans who attended that show will be offered free tickets to the benefit concert at the Old Trafford cricket ground, with the rest sold to raise money for the affected families.
"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," Grande said.
Grande is a favourite of pre-teens and as well as the children killed, a number of the victims were parents who came to pick up their daughters.
'A lot of unease'
The train station next to the attack site reopened earlier on Tuesday for the first time, as life in Britain's third-largest city resumed a semblance of normality.
"There's still a weird feeling, you know, armed police, a lot of unease," said 59-year-old David Keys as he got off a train at Manchester Victoria.
Sharon Glyn, 48, said she felt "goosebumps" as her train pulled into the station.
Troops were deployed at key public sites last week as Britain's national terror threat was raised to maximum, and police hunted suspected accomplices of bomber Salman Abedi.
Watch: Manchester residents honour victims with bee tattoo
The 22-year-old, who was born in Manchester to Libyan parents, was killed in the attack, which was claimed by the Islamic State group.
Britain's threat level was reduced back from "critical" to "severe" on Saturday, and the army has been stood down, but 14 people remain in custody in Britain.
Abedi's brother Hashem and father Ramadan have also been arrested in Libya, where authorities say the two brothers were both IS jihadists.
Questions are growing over whether intelligence services missed any vital clues, after a report in the Mail on Sunday that US authorities had previously warned Britain's MI5 intelligence service about Abedi.
British police revealed Tuesday that Abedi had appeared in police records over theft, receiving stolen goods and assault in 2012 but was never flagged up for any radical views.
"He was known to the police for some relatively minor matters," Manchester police chief Ian Hopkins told BBC radio, adding: "I am not privy to what the security service did or didn't know about the individual at this time."
Election issue
The attack took place just weeks before the June 8 general election, in which Prime Minister Theresa May is seeking an increased parliamentary majority.
After a three-day suspension in campaigning after the bombing, May's Conservatives stepped up their criticism of opposition Labour leader Jeremy Corbyn, accusing him of being soft on security.
But May - who served as interior minister for six years before taking office last year - has also come under heavy criticism for drastic cuts in police numbers.
She insists that while overall numbers of officers have gone down, budgets for counter-terrorism policing have risen.
Watch: MI5 reviewing practices after Manchester attack
Abedi reportedly fought in the Libyan conflict to topple former dictator Moamer Kadhafi.
Police released a security camera image of Abedi carrying a large blue suitcase, appealing for any information about where he might have been.
"We are just trying to make sure we capture everything that he has discarded so we can then see what the significance is," police chief Hopkins said.
"Has it [the suitcase] got DNA on it of people that may have helped him? Has it material he may have used?"
Manchester-born Oasis frontman Liam Gallagher was to make his solo debut later on Tuesday with a charity concert.
Like Grande's, it will also raise money for the "We Love Manchester Emergency Fund" set up by the local council and the British Red Cross, to help the grieving families and victims.
