BYU Hawaii and the surrounding community gave a welcome worthy of a superhero to Hawaii-born actor Jason Momoa on Thursday, when he encouraged the crowd to sign up to donate lifesaving bone marrow or blood stem cells to those in need.

Momoa, best known for playing the title role in the 2018 blockbuster “Aquaman” and for portraying warlord Khal Drogo in “Game of Thrones,” rode up to the Laie campus on a motorcycle and was greeted by a throng of cheering admirers. He hoisted up Rhyder Lopez, a 6-year-old from Waipahu who is in search of a match for a bone marrow transfusion to treat a rare blood disorder.

Momoa was the main attraction in an event organized by BYU Hawaii’s Healthcare Professionals Club and Be the Match, a division of the National Marrow Donor Program that maintains a registry of potential bone marrow and stem cell donors. According to Be the Match, a bone marrow transplant can be used to treat more than 70 diseases, and for many it is the only proven treatment. Meanwhile, there is an acute shortage of donors, particularly in Pacific Island communities.

“We are all here to help Rhyder,” Momoa said to the crowd. “It’s pretty crazy, the statistics of what’s in the registry. I learned today (the number of people in the registry is) a half of a percent in the world. Not even 1%. If we were all one tribe and we lived here in Laie, say it’s 1,000 people, and two people were sick, wouldn’t we all go there? Wouldn’t we all go there to swab our cheeks just to help our community?”

Rhyder was accompanied by his family, including his brother Rhaiden, 9, who himself needed a bone marrow transplant at age 9 in 2015. The boys’ mother, Iza Lopez, said the family had to travel to Cincinnati for the operation — a journey made even more complicated because she was pregnant with Rhyder at the time.

“We were actually there for a year and a month, because we got backed up,” she said. “I ended up giving birth there. … He was a C-section baby.”

Momoa got involved in advocating for the donor registry through his friendship with part-time Kauai resident Travis Snyder, who was diagnosed with acute myeloid leukemia in 2015. Snyder is known for organizing the Color Run, a series of 5K runs held around the world as fundraisers for charity.

“He’s got three children and he’s fighting for his life. Turns out he has a little bit of Polynesian in him, and he could be the whitest person I know,” Momoa told the crowd with a laugh. “So you could really be a help.”

Snyder has been treated twice, once with chemotherapy and a second time with a stem cell donation from his brother. But his cancer returned in March, and another stem cell donation has been deemed his best chance at remission. It was recently determined that someone with Pacific Island ancestry would likely be the best match.

“They’ll do some surface testing of your genetics and do the match, and then researchers will go the next level and try to identify the exact components of my illness, and they found it’s a more difficult match,” Snyder said in a phone call from Los Angeles, where he is while waiting for a match.

He said he has known Momoa “since before ‘Aquaman’ took off,” initially meeting through mutual friends on Kauai. “He had a bit more time on his hands, and our kids all had fun together,” Snyder said. “He’s part of the magic of Kauai and that aloha spirit.”

The BYUH registry drive was held over two days, with about 110 students signing up Wednesday. That number likely was surpassed significantly Thursday, when a long line of potential donors snaked into the BYUH Aloha Center ballroom to swab their cheeks and start the registration process.

Many came from outside BYUH, such as Khrystine Felipe, who is vacationing on the North Shore and heard about the event through Momoa’s posts on social media. “If I have a chance to save a life or help someone in need, I will if I can,” she said. Felipe was born in Hawaii but now lives in Sacramento, Calif.

Allison Legaspi, a freshman at BYU Hawaii from the Philippines and a member of its Healthcare Professionals Club, got her cheek swabbed Wednesday, to “have a chance at saving a life.” She said it was important to get “a diversity of people to get their cheeks swabbed in order to get more matches.”

For more information on the donor registry, visit bethematch.org.