Frontwoman Florence Welch announced the concert earlier this month (Jul15) but the details of time and place were only made public the day before the gig (23Jul15).

In a message posted on Twitter.com, she wrote, "Sydney: Florence + the MAChine play a free show tomorrow at Mrs MACquarie's Chair at 12:30 pm. Looking forward to seeing you."

Around 500 fans crowded the stage on the waterfront overlooking the Sydney Opera House and Harbour Bridge to catch the stripped-back 40-minute set.

The band is scheduled to headline the Splendour in the Grass festival at North Bryon Parklands on Saturday (26Jul15). Mark Ronson and Blur are also set to perform over the weekend (24-26Jul15).