Ryan Reynolds is paying a long-awaited tribute to Rob Delaney's late son.

The "Deadpool & Wolverine" producer and star took to Instagram Monday to explain why the tribute to Delaney's 2-year-old son Henry came now rather than in "Deadpool 2." Henry died in February 2018, months before the second "Deadpool" film was released.

"There's more to @robdelaney than some realize," Reynolds, 47, captioned a carousel of movie and set photos featuring himself Delaney, 47, as Peterpool (aka Sugar Bear) and Hugh Jackman's Wolverine. The "Catastrophe" actor wrote about losing his son in the book "A Heart That Works," with Reynolds calling him a "beautiful, acerbic and vulnerable writer."

Reynolds then recalled Delaney losing his son "right after" they finished shooting "Deadpool 2."

"If you stayed through the credits of Deadpool & Wolverine, you might notice a credit saying, 'For Henry Delaney,'" Reynolds continued. "I've always kicked my own ass because I didn't place a tribute to Henry over the end credits of DP2."

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The tribute comes as "Deadpool & Wolverine" earned $211 million at the domestic box office its opening weekend and broke several records, including the largest opening for an R-rated movie. "If there's a bright side, even more people are seeing Henry's name in the credits of Deadpool & Wolverine," Reynolds said.

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Reynolds spoke about Delaney's memoir, recalling the author's unique perspective on losing a loved one.

"Rob has a vivid perspective on unimaginable grief. And he takes an unfiltered, rage-ful, loving, sad and hilarious (yes, HILARIOUS) look at grief through his book," the "If" star gushed.

"I'm lucky to know Rob. And I'm lucky to have friends willing to put themselves on the line to make others feel less alone," said Reynolds.

In "Deadpool & Wolverine," Delaney plays Peterpool aka Peter Wisdom, a friend and co-worker of Reynolds' Wade Wilson and former member of the mutant superhero team X-Force, led by Deadpool and Cable, despite his lack of powers or skills.

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The third of the actor's four sons with wife Leah Delaney died following a battle with brain cancer.

Delaney told USA TODAY in 2022 that the hoped the memoir would help parents and siblings who have suffered similar losses. He also pledged his earnings to children's hospices.

"I know I've benefited from my bereaved parents groups that I go to," he said at the time. "So if I am honest about my experience with somebody whose kid died three weeks ago or six months ago, that's going to help them. I know having the book out there is good. Aspects of getting the book out there are painful for me, but I'm willing to do it to get the book to people who need it.”

Contributing: Brendan Morrow and Erin Jensen