Jason Momoa has raised the spirits of a young cancer-stricken Aquaman fan in Massachusetts with a sweet surprise video call.

The action star became a real-life superhero by giving seven-year-old Danny Sheehan a ring over FaceTime on Wednesday as the superfan battles rare forms of brain and spinal fluid cancer, a moment that was captured in footage shared online.

"So I just wanted to say thank you to the community, friends and family on Instagram for reaching out and showing me this beautiful boy Danny who is going through chemo and has cancer," Jason captioned a post on the site that featured a clip of the tender exchange.

"I saw his video online that made me want to get in touch and FaceTime him and spend some time talking to him," he added.

Danny could not contain his delight in the footage, gushing: “Hi Aquaman! I’m so excited," before being gifted with an Aquaman toy.

Jason also urged fans to donate to Danny's GoFundMe fundraising account before imploring Aquaman franchise bosses at Warner Brothers to gift the little boy an official trident.

"Hey @wbpictures let’s get Danny a (sic) Aquaman Trident!," he shared.

Jason's post has helped Danny's family raise around $120,000 (£90,000) for his medical expenses, which exceeds their initial $75,000 (£56,000) goal.