NHL star P.K. Subban has released a heart-wrenching video showing patients at the Montreal Children's Hospital reading a letter he wrote to them.

The former Canadiens defenceman promised "many more surprise visits" to the hospital despite being traded to the Nashville Predators this summer.

"You might think that I'm doing so much for you, but the truth is you do so much for me," he wrote.

"You can't imagine how rewarding it is to watch you get better and leave the hospital with your families," reads one patient, who couldn't help but tear up.

I wanted my friends <a href="https://twitter.com/HopitalChildren">@HopitalChildren</a> to know that I will never stop fundraising for them. So I wrote a letter...<a href="https://t.co/giImuJz4ou">https://t.co/giImuJz4ou</a> —@PKSubban1

Subban also said he would follow through on his pledge to raise $10 million for the hospital.

"Just because I have a new address, it doesn't mean that my commitment to you and the hospital is going to change one bit," Subban wrote.

Subban was in Montreal earlier this week to host a Just for Laughs comedy gala.

During his stand-up segment, he took the opportunity to take a few jabs at Habs' management. He also thanked the team for helping him get his start in the NHL.

The comedy show raised $130,000 for the hospital.