The action star had already introduced seven-year-old Danny Sheehan, who is battling rare forms of brain and spinal fluid cancer, to his fans, during a FaceTime chat last month (Nov20).
After the call, Momoa had issued a plea to Warner Bros. to gift Sheehan an official trident, and it seems they came through.
Sharing a snap of Danny surrounded by hordes of "Aquaman" merchandise, including a trident, on his Instagram page on Sunday (06Dec20), Momoa wrote, "Wanted to share a picture of this amazing boy Danny Sheehan, Natalie his mom sent me this today. I wanted to say thanks to Andy Smith @sideshowcollectibles for putting some action figures and toys together for Danny and @wbpictures for sending over a Aquaman trident."
In the last image, a note from "Uncle Aquaman" could be seen, in which he promised to "ride some dolphins" with Sheehan.
Danny's mother Natalie told Yahoo! Entertainment her son was left "speechless" upon receiving the gifts - and his response, considering he's usually "so talkative" was a "true testament to how surprised he was."
"My reaction was one of sheer delight, surprise and gratitude," she added. "Danny had a rough week this week, so it was great to see him so lively and excited."
Jason decided to surprise Danny after a home video of the boy unwrapping an "Aquaman" gift went viral. "Oh my gosh, my favorite one," he exclaimed in the clip. "Aquaman!"