Pharrell Sings 'Happy' To 8-Year-Old Leukemia Patient

(Radio.com) Pharrell's biggest fan got the surprise of a lifetime: 8-year-old Reef Carneson suffers from acute lymphoblastic leukemia and asked the producer and musician for a FaceTime session.

When Pharrell heard his story, he invited Reef to his Philadelphia show last Saturday night. Because of his compromised immune system, Reef wasn't able to fly from his home in Cincinnati to Philly for the show.

So Pharrell hooked him up with a private car, five-star hotel accommodations, and backstage passes. During his performance of 'Happy," Pharrell invited Reef onstage to soak in the moment with his idol. Watch the video here.