Wearing a flowing dark pink dress made up of wide ruffles and boasting a plunging neckline, the acclaimed songstress joined the British redhead for a moving rendition of his hit ballad at the Global Citizen Festival in Johannesburg, South Africa, on Sunday.
Global Citizen, an advocacy group, campaigns for an end to extreme poverty, and other causes.
'This is amazing!' festival host Trevor Noah said as Trudeau's tweet was shown on a big stadium screen. Many people got tickets to the concert through charity work and petition-signing.
Police have encouraged victims to open cases.
While the Global Citizen Festival went off largely without a hitch yesterday, there have been several reports of muggings after it ended.More news: Citizens urged to get tested for HIV
She said the muggers were even pulling knives and guns on the defenceless revellers.
Police arrested one suspect in the theft of a cell phone, police Brig.
The City said: "As part of the Venue Operation Centre (VOC) team, the Johannesburg Metropolitan Police Department was responsible for traffic management and deployed 236 metro police officers/ traffic wardens, 104 JMPD patrol vehicles, 18 JMPD motorbikes and 11 horses to ensure traffic free flow from 6:00 am on 2 December to 7:00 am on 3 December".
Sun pointed out that world-renowned band Guns and Roses attracted almost 65 000 fans to their concert at the same stadium just three days before and the event was an overall incident-free one - except for a report of suspected domestic violence.