The star-studded One Love Manchester benefit concert was organised by Ariana to raise money for those affected by the Manchester terror, where 22 people were killed and more than 100 injured.
Ticketmaster sold tickets to the event, with those who were at the Manchester concert eligible for free tickets.
Early figures suggest more than £2m has been raised for the victims. All the artists are performing for free while concert promoter Live Nation has underwritten the cost of the event,Daily Mirror reports
It's thought the concert tonight will have more viewers than Live Aid as its broadcast to more than 50 countries, as is streamed online.
The gig is on target to beat the 600m who saw Nelson Mandela's 70th birthday tribute concert in 1988.