When the well known Habanera aria from the opera Carmen by Bizet suddenly rang out across the River Traders Market on Saturday, the crowd of around 300 stopped and gasped.
Even though some knew the "flash opera" from the students of the New Zealand Opera School at Collegiate School was going to happen, the actual event thrilled most who were there.
"Well, suddenly I heard this beautiful voice singing and then young people were walking past me singing. I just loved it, I really did,"one man said.
"It wasn't long enough. I wanted more, a lot more," a woman said.
Singing the role of Carmen was Dame Malvina Major Emerging Artist Bianca Andrew, who wowed the crowd with her rich mezzo soprano voice and sultry moves.
Twenty-one students walked in from different corners of the market and the riverbank singing the chorus, surprising everyone they passed.
The market was first treated to a flash opera by students two years ago. It made such an impression that dozens of onlookers rushed to book seats for the final concert at the Royal Wanganui Opera House, as well as generating significant media attention.
However, the rush on tickets will not happen this year as the final night concert, Great Opera Moments, at the Royal Wanganui Opera House on Saturday has been sold out for three weeks.
Opera school director Jonathan Alver said a second concert is being mooted, possibly for the 20th school in 2014. After their snappy, spectacular performance, the students had to rush back to Wanganui Collegiate School for 11am classes.
Mr Alver said he understood that people wanted to hear more, "but it's just a quick flash ... the flash mob sings and goes ... that's it."