British pop superstar Ed Sheeran shocked a young fan Sunday at West Edmonton Mall, when he walked onstage at a fundraiser to sing one of his hit songs with her.

Sydney Bourbeau was performing Sheeran’s Thinking Out Loud as part of her music school’s fundraiser for the Edmonton Humane Society when the red-headed singer walked out of the HMV store and on to the nearby stage, gave her a hug and finished singing his song with her.

Bourbeau said at first she couldn’t quite believe her musical idol was really standing there with her. She thought someone had just come onstage to fix her microphone, until the crowd starting cheering.

“I was like, should I stop? I didn’t want to stop, but I wanted to talk to him,” she said. “This is, like, the best thing that’s ever happened to me.”

The 13-year-old has been taking singing lessons with Resonate Music School and Studio, which hosted the fundraiser, for almost a year, but said she’s been singing “forever.” She’s been a big fan of Sheeran since his first studio album was released in 2011, she added.

Sheeran left the stage after the performance, stopping for some selfies with fans along the way. But Bourbeau received another shock later Sunday afternoon when Sheeran’s manager texted her, offering two tickets to the Grammy-nominated singer’s Sunday night concert at Rexall Place. She planned on taking her mother with her.

Resonate Music School president Michael Cathrea said the impromptu duet with the singer came as a shock to the entire crowd, which also raised about $10,500 for the Edmonton Humane Society.

The music school didn’t know Sheeran was at the mall, nor did they plan their fundraiser around his Edmonton concert, Cathrea said.

“That’s a once-in-a-lifetime experience. He happened to be there, she’s singing his song … It was amazing that she was actually able to keep it together and finish,” he said of Bourbeau. “It was shock, as if she had seen a ghost.”

“I was so happy that he did that,” Bourbeau said through tears. “It was incredible.”