Ryan Reynolds is paying tribute to one of his biggest fans.

The 39-year-old actor first talked about Connor McGrath, a 13-year-old Canadian boy who was battling cancer, in February, when he surprised McGrath with a special screening of Deadpool. Sadly, Reynolds revealed on Facebook that McGrath died on Tuesday.

"For three straight years, my friend, Connor McGrath drop-kicked cancer... Not sure how... Maybe the cancer cheated... But the fight came to an end two nights ago," Reynolds wrote in an emotional post on Thursday. "He went way too early and it's impossible to reconcile. Connor was a great friend, a great son, and a light to the people lucky enough to know him. While repeatedly punching cancer in the balls, he made everyone laugh."

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Reynolds talked about the close friendship the two shared, recalling McGrath's smart and funny personality.

"I called Connor, 'Bubba.' And he called me 'Bubba2,'" Reynolds shared. "We met because he loved Deadpool. In a certain sense he WAS Deadpool. Or, at least everything Deadpool aspires to be; balancing pain, fearlessness, love and a filthy (filthy!) sense of humor in one body. I wish he could've stuck around a lot longer."

Still, Reynolds is thankful for the time the two spent together.

"I'm grateful I got to orbit Connor's world for a brief time," Reynolds reflected, also revealing the two met through the Make-A-Wish Foundation. "Grateful for the pages and pages of hilarious texts between us. Grateful to his parents for allowing Connor to spend time with a foul-mouthed child in the body of a 39-year-old."

"See ya down the road, Bubba," he concluded.

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In February, Reynolds traveled to Alberta, Canada to show Deadpool to McGrath at the hospital, making his pal the first person ever to see the Marvel film.

"He's my friend," the actor wrote on Facebook. "I know lots of celebrities jump up and down touting a cause -- and maybe I'm no different. But holy frozen sh*t-slivers, I love this kid. He's the GREATEST."

Watch the video below for more on Reynolds' and McGrath's special friendship.