Jason Momoa continues to call on his fans to change things.
The actor, 42, shared an Instagram post on Friday, where he again pleaded with his followers to become potential donors to Be The Match Registry, a national bone marrow donation program, amid the battle with cancer of his friend Travis Snyder.
“Aloha everyone,” Momoa began in a video, which sees him posing shirtless in a field. “As you saw recently, I talked about my friend Travis who is fighting cancer for the third time, and how important it is that we increase the stem cell registry for him and the thousands of others who need matches.”
“First of all, I just wanted to say thank you very much [to] everyone involved. I’ve seen it, it’s beautiful, and we’re starting to have an impact, so please let’s keep it going,” said the Aquaman star continued.
Momoa added, “We can all make a difference together. Please join the registry. All you have to do is dab your cheek and save someone’s life. Be a hero – a real hero. “
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Momoa reiterated her statement in the caption of her post. He also shared photos of Snyder’s three children – Hank, Miles and Luke – in his slideshow, detailing how their father “needs a match”.
“Love these boys,” Momoa wrote alongside a photo of Snyder and his three sons. “They watched their father battle cancer for 7 years. His only hope for recovery now is to find a match in the registry. Please help them and thousands of others.”
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Momoa also shared the same posts on her Instagram Story, alongside a video of her PEOPLE interview with Snyder from last month.
The star also included a note that “only 2% of the population is on the stem cell registry, which means cancer patients are dying waiting for a match. Every day.”
RELATED VIDEO: Jason Momoa calls for donors for Be The Match registry inspired by friend’s cancer
In late May, Momoa called on more “heroes” around the world to step up and help Snyder in his fight against acute myeloid leukemia, which he was diagnosed with in 2015. The disease is a type of cancer in which the bone marrow makes a large number of abnormal blood cells – the most common type of acute leukemia in adults – according to the National Cancer Institute.
It can be treated with a blood stem cell transplant, which replaces unhealthy blood cells, but Snyder initially had no full matches in the Be The Match registry. He underwent chemotherapy, which put his cancer into remission. Since then, the husband and father of three has relapsed three times, most recently in March, which forced him to look for a donor again.
“[When I was first diagnosed] you receive the worst leukemia card and you have no match. It was really difficult,” Snyder previously told PEOPLE. “Through all of this, I think of my kids. Each relapse was the hardest conversation to have with them. I just want to be able to keep raising these boys.”
Snyder also praised Momoa for standing by his side and offering to help in any way. “Some of my friends shrink when you’re in trouble, or it gets a little superficial,” he said. “And Jay was right there again.”
Momoa, who has aged from being a donor candidate, has since vowed to use his platform to encourage others to join the registry in case they match someone in need. “I’m supposed to be a superhero,” the actor told PEOPLE. “And you think, ‘God, anyone at any time, if you’re just on the registry, you have the opportunity to save a life.'”