In a message to fans posted on his Facebook account, the singer revealed that he had partnered with Children's Miracle Network and would donate a portion of proceeds from My Worlds Acoustic to the organisation.
"I made a promise to you guys when I wrote 'Pray' that I would use it to raise money for charity for the holidays," he wrote. "I'm keeping my promise. We can all make a difference if we make an effort. Thanks for always being there."
He added a message on his Twitter account which said: "Receiving is great... but nothing compared to giving. #HELPOTHERS (sic)."
Children's Miracle Network - which raises money and awareness for 170 children's hospitals across the US - also revealed the partnership on its own Twitter feed and thanked Bieber for his gesture.
"Justin Bieber is on Santa's nice list!" said one message. "He's donating a portion of proceeds from #myworldsacoustic to @CMNHospitals."
My Worlds Acoustic will be available through Walmart from tomorrow.