The “Boyfriend” singer continues to melt hearts with his boyish smile and sweet-hearted swag.

Just days after a stopover with Crystal Montgomery, an 18-year-old battling shoulder cancer, Justin Bieber has met for some quality time with another cancer victim. Hailey Roser, a four-year-old suffering from a brain tumor, got a visit of a lifetime from the boy wonder himself. 

The family of the brave youngster and self-titled superfan shared details of the visit on a Twitter account set up for the “Healing Hailey” movement.

@justinbieber thank u for making mine and my daddy @therealroser and my mommy @sabrinaroser1 dream come true #BELIEVE twitter.com/Healinghailey/…

— Hailey Roser(@Healinghailey) October 22, 2012

The adorable 4-year-old beamed, smiling from ear-to-ear in a purple flower headband and matching Belieber T-shirt, circa My World 2.0. (Yes, she’s been a fan since she was two…What’s your point?)

Before the Biebs took to the stage, he and Hailey hung out for a good five minutes backstage during a Milwaukee, Wisconsin stop of his tour on Sunday.

A special thanks to children's hospital, the MACC fund, Bell ambulance, Netjet and @justinbieber and his team. twitter.com/Healinghailey/…

— Hailey Roser(@Healinghailey) October 21, 2012

Following the visit, Justin responded to the photo and message, thanking Hailey for the opportunity to meet with her.

@healinghailey thank u :) stay strong

— Justin Bieber (@justinbieber) October 22, 2012

Hailey’s efforts to meet with Justin came after a long social media and publicity campaign, including an appearance on the celebrity gossip show TMZ Live.

As we previously reported, Justin visited with Crystal Montgomery last week. The singer surprised Montgomery after her best friend Joana Antunes got in touch with the 18-year-old icon via Twitter.

“She cried happy tears and was in shock to see him,” Joana said at the time.

Kind, compassionate and selfless…Yes, they grow ‘em right up there in Canada.