On Monday, the 47-year-old action star shared a sweet Instagram video of himself singing Maui's signature song "You're Welcome" for a 3-year-old boy named Aiden Snyder, who's facing an unspecified medical challenge.
Johnson begins his message by calling Aiden "the coolest kid on earth" and thanking him for being a fan of his shape-shifting demigod character.
"I know you have no idea who I am," Johnson says. "You're like, 'Who is this big bald man with the big head?'" After revealing he's the actor who voiced Maui in the movie, he launches into song, and cutely enlists the family's dog to help him.
Afterward, Johnson wishes Aiden well, saying, "I want to tell you, most importantly, stay strong and you are inspiring everyone around you, including me. Now I'm your biggest fan. Probably literally your biggest — as in size — your fan."
The actor captioned the video "To a VERY special and strong 3yr old lil’ boy, Aiden Snyder. I found out that lil’ Aiden LOVES, my character 'Maui' from MOANA, and Maui has gotten him thru many treatments, clinic sessions and hospital visits."
"These are tough times we’re in, but this boy’s struggles and fight has a way of putting things into perspective for all of us," he added. "Sending so much love and strength to Aiden’s mommy and daddy, Dan and Natalie Snyder in Philadelphia. Stay strong, Aiden and remember... you’re way more powerful and awesome than I will ever be. Love, Maui ❤️💪🏾"
It's the second time in recent weeks that Johnson's used his Maui character to help a child.