"It's pretty much a fact that you have more courage and more strength in your pinky finger than any superhero does in their entire body," Reynolds said in a video message.
Evans jokingly gave Josh a hard time for being a bigger Deadpool fan than Captain America, the superhero he portrays in the Marvel Universe. Evans also sent his get-well wishes: "Hope you're doing good today and take care."
Pratt also joined in and sent a video message to Josh that is out of this world.
The "Guardians of The Galaxy" actor, who portrays Star-Lord, said: "I think real heroes are young people like you have to face challenges and do so with the bravery... that you do."
Pratt added that he hopes his heartfelt words will "help put a smile on your face."
Tom Holland's spidey senses must be tingling because the "Spider-Man: Homecoming" star hopped in on the action. He said, "I am thinking about you and everyone at Marvel is thinking about you."
The actor added that he is "filming Spider-Man, far from home."
Hugh Jackman, aka Wolverine, encouraged Josh to stay strong like the mutant he plays in the "X-Men" film series, adding: "I am sending you lots of positive thoughts, keep fighting."