Singer-songwriter Shawn Mendes took a break from screaming fans and bright lights to perform for a small group of sick children at a Toronto hospital.

"For these kids, I could imagine how it feels like the whole world's on their shoulders," the 16-year-old Pickering, Ont. native told CTV Toronto's Ben Mercer at the hospital on Thursday.

The pop star met up with young patients at Toronto's Hospital for Sick Children, in support of Duracell's "Powering Smiles" campaign and the Children's Miracle Network.

He said he hoped to be able to get the young patients' minds off their circumstances, "even if it's just for a second."

Mendes sat on a wooden stool at the front of a quiet room with his guitar, performing several songs for an audience of children and teenagers hooked up to live-saving equipment and IVs.

"I'm shy, and if you sing, it'll make me feel better," Mendes told the room of smiling children.

"Then after, we can hang out and play games. Whatever you want to do."

After the small concert, Mendes stuck around for the afternoon, playing air hockey and taking photos with patients.

He hopes the campaign will show how important it is to have fun, especially for children. He said he's trying to use his influence as a celebrity to raise awareness for the hospital.

"It was really exciting," a young patient named Keira told CTV Toronto after high-fiving the singer. "He's cute. And I like his songs."

The intimate concert was a sharp contrast from the singer's last performance in front of a crowd of thousands of fans at the Much Music Video Awards on Sunday.

"Growing up I always knew about (the MMVAs) and always watched," he said.

"I actually went and I was in the crowd three years ago watching the show as a fan, and then last year I walked the carpet and I got to watch all these acts do their thing."

This year, Mendes won the award for favourite fan video for his hit "Something Big."

"The craziest part is that it wasn't that long ago that I wanted to do this," he said.

Mendes says he feels lucky to have the opportunities he's had, but told teenage fans they too can achieve success through hard work.

"What I would say to a kid wanting to do what I did is to just put your heart into it," Mendes told CTV's Canada AM on Thursday.

Mendes released the music video for his new song, "Stitches" on Wednesday night, and the video had more than 400,000 views by Thursday morning.

Despite his success, Mendes said his friends and family in the Toronto area act like nothing has changed. The singer said returning to Pickering, Ont. is what keeps him grounded.

"Once I come home it feels like nothing's ever changed," he said.

"We don't really talk about it. It's kind of just like this is my job, it's what I do... Everyone is really, really awesome about it."