WATCH: Simon Cowell wowed by Irish singer's emotional song on America's Got Talent

Cork singer Stephanie Rainey has wowed the judges and sailed through to the next round on 19th series of America's Got Talent.

36-year-old Stephanie performed an original song for judges Simon Cowell, Sofia Vergara, Heidi Klum and Howie Mandel, explaining that she wrote the track, Please Don't Go, after the tragic death of her nephew the day before his first birthday.

The emotional track reduced the audience to tears with Simon Cowell commenting afterwards that it was the best new song he's heard this year "by far."

"And your voice is beautiful. A lot of people are going to resonate with that song. I absolutely love this," the music mogul added.

He even joined Rainey onstage after her performance and said: "That was what I call a moment. That song is so beautiful. Thank you so much."

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The Cork woman also won praise from the three other judges. She received four yeses and advances to the next stage of the talent show. 

Stephanie explained that she was signed to a deal after her video for Please Don't Go attracted a million views in one day but that the journey in the music industry to date had been "very hard."

"I've had a very rollercoaster career I would say," she told the judges.

"This song that I'm going to play has had a big moment in the past. We made it in a tiny room and put it up one Monday morning and by the end of the day it had a million views.

"And then I signed a deal after the song came out. I think I probably didn't fully know who I was when I signed that deal.

"The journey from then to now has been hard. It's a tough industry, you have to be resilient. You have to be willing to pick yourself back up. So here I am."