LONDON - The mall's food court is packed with fast-food shoppers.
A pianist in one corner plays some generic Christmas songs.
Then a young woman in a red scarf, her cellphone to her ear, rises from her chair and starts to belt out the "Hallelujah Chorus" of Handel's Messiah.
Her pure, powerful soprano voice carries across the crowd and halts diners in mid-bite.
Other "shoppers" leap to their feet or converge from the halls for a full-on, spine-tingling chorus - a flashmob performance that's generated more than 3.1 million YouTube views just 10 days since it was posted.
The woman in the red scarf is soprano Stephanie Tritchew, 22, a student at the University of Western Ontario's Don Wright Faculty of Music.
She's as surprised as anyone that the video has made her a minor star, along with the 100-member Chorus Niagara who sing with her - far beyond Welland's Seaway Mall where the performance took place this month.
"I thought it was a really fun thing to do. But I had no idea it would get to this," Tritchew said Monday.
Tritchew, who has an undergraduate degree from UWO and has begun her first years of master's studies there, auditioned last summer for Chorus Niagara's performance this Dec. 11 and 12.
And when the chorus's artistic director Robert Cooper - himself a UWO grad and a member of the Don Wright Music Faculty's Hall of Fame - asked her to be lead soprano for the Welland mall flashmob, she eagerly agreed.
The mobsters' instructions were to act as regular shoppers and diners until the last bars of Jingle Bells faded away. The event's success depended not just on musical artistry, but also on split-second timing and surprise.
Tritchew calmed her nerves by phoning her sister, Stacey, also a UWO student, as part of her shopper schtick.
Other performers include a "custodian" carrying a wet-floor sign and a couple ordering food.
Shoppers' surprise gives way to delight. Some start to sing along; others appear teary-eyed. Grandmothers hug their beaming grandchildren and several people record the event on their smartphones.
The flashmob - a seemingly spontaneous gathering that disperses as quickly as it appears - took about eight weeks to organize and the video uses seven hidden cameras and the natural acoustics of the food court.
It was meant to be a thank you from AlphabetPhotography.com to its clients, said Chris Dabrowski, public relations director for the Niagara Falls' company that conceived of and produced the video.
It's gone far beyond what anyone imagined, he said. "Our goal was to spread Christmas cheer, but we never expected it to reach around the world. We never would have expected it to reach 100,000 (views), then 500,000, then three million."
The event took place Nov. 13 and was edited and put online Nov. 18.
Since then, the woman in the red scarf, whose family is from St. Catharines, has drawn attention from strangers as far away as Switzerland and Australia.
"They say, 'we just want to let you know that you brought joy to our lives.' It's just really touching to get that reaction from people," Tritchew says.
Her voice professor, UWO's Sophie Louise Roland, was gratified so many have been captivated by her student's performance. "I think she did wonderfully."
And, Roland said, it was doubly gratifying to see classical music performed in a public venue accessible to so many people.
For those who can't get enough of Tritchew's voice, the performer will play the role of Marcellina in Mozart's The Marriage of Figaro to be performed at Talbot Theatre on campus Jan. 28-30 and Feb. 4-6.