The video was shared by the Los Angeles Police Department last week.
ADVERTISEMENTA video of a woman singing an aria by Italian composer Giancomo Puccini on an L.A. subway platform has become a social media sensation, racking up hundreds of thousands of views across the world.
The clip, understood to have been captured by an Los Angeles Police Department (LAPD) officer, shows the woman singing the operatic aria "O mio babbino caro" as she stands loaded with bags on the platform.
Several Twitter users replied to the LAPD's Twitter post to say they recognised the woman, and she later appeared in an interview with NBC Los Angeles.
Named by the news channel as Emily Zamourka, the report described her as a woman who grew up in Russia and had hoped to become a singer, but had recently been left homeless.
"I'm sleeping where I can sleep," Zamourka told the NBC in the interview and added she sang in the metro "because it sounds so great".
The clip posted on LAPD's social media account with the caption "4 million people call LA home. 4 million stories. 4 million voices... sometimes you just have to stop and listen to one, to hear something beautiful" had been watched over 280,000 times by Monday.