Simon Cowell was left sobbing after being reunit­ed with a "Britain’s Got Talent" star whose life he changed.

The ITV show boss — known for his Mr. Nasty persona — could barely speak at Saturday’s auditions after 17-year-old Julia Carlile took to the stage for the first time since he paid £175,000 ($214,049) for her spinal operation.

I’m told Julia, who dances with Scouse group MerseyGirls, left barely a dry eye at London’s Wembley Arena as she showed off the success of her US treatment — even backflipping across the stage.

It completes an incredible turnaround for the youngster.

Simon stepped in two years ago after hearing how the BGT finalist suffers from scoliosis and might never dance again.

He paid for an operation to correct her curved spine in August 2017.

Following Saturday’s performance, Simon’s fellow judge Amanda Holden asked the mogul to speak — but he managed just a few words before handing the mic to the other judges, ­wiping away tears.

Amanda rubbed Simon’s arm in a show of support.

Simon left the judging desk to compose himself, standing in the shadows at the side of the stage.

He then told Julia and her fellow dancers: “All I want to talk about is one person’s strength and, beyond that, the friendship and support you all have, which we saw the first time we met you.”

His voice then began to crack after he said: “To see you able to come back tonight... it just means everything...”

Fellow judge Alesha Dixon said: “That just made my heart soar. Simon, I love you, I love what you’ve done for her.”

Julia said: “I thought that now I would be at home not dancing for the rest of my life — but here I am backflipping with my best friends.

“I couldn’t walk two years ago and now I am here.

“Simon, thank you so much. I don’t think I have ever been so happy as I am right now.”

In his role as a talent mogul, Simon has changed hundreds of lives over the years... but surely none more so than Julia’s.

This article originally appeared in The Sun.