The actor took to on Thursday (28Apr16) to share a heartfelt and witty post dedicated to Connor MCGrath, who had been the first member of public to see his portrayal of Marvel superhero Deadpool on the big screen, prior to its release in February (16).

Ryan met Connor and his family through the Make-A-Wish foundation earlier this year (16) and became close friends before the 13-year-old died following a three-year battle with leukaemia.

The star's Facebook tribute honoured his "funny, great friend", who had passed away too soon.

"In my wildest dreams, I can't imagine how hard this is for his parents Kim and Gerald - along with his extended family in Newfoundland," Ryan wrote. "Connor was 13. But this kid... He was smart. He was funny. And not just funny 'for a kid' - or funny 'for a person battling something awful'. He was unqualified funny. He had that... thing. He went way too early and it's impossible to reconcile."

Describing the his fellow Canadian as "a great friend, a great son, and a light to the people lucky enough to know him", Ryan revealed he made everyone laugh, including the staff who cared for him at Edmonton's Stollery Children's Hospital, all while "repeatedly punching cancer in the balls".

The actor also revealed Connor was the first person to see R-rated movie Deadpool.

"I travelled up to Edmonton, Alberta to surprise him with a rough cut of the film," he continued. "There were still huge sections with wires we hadn't yet painted out, jokes which weren't working (and still aren't) and green screens. Connor didn't seem to mind. And I'd never felt luckier to get to be Wade Wilson (Deadpool)."

He then quipped, "Before you jump down my throat for showing a 13 year old an R-Rated film, please know this kid knew more swear words than a British chef!"

Ryan, who is said to be expecting his second child with actress wife Blake Lively, then encouraged his fans to make a donation to the The Make-A-Wish Foundation.

He signed off on the moving tribute to Connor by writing, "See ya down the road, Bubba."