Boston Celtics star Kyrie Irving and his older sister were officially welcomed into their mother’s Standing Rock Sioux tribe on Thursday.

The All-Star guard and his sister, model Asia Irving, visited the tribe’s reservation that straddles the North Dakota-South Dakota border and took part in a ceremony recognizing their tribal heritage and support for the tribe’s long battle against the Dakota Access oil pipeline.

In front of a packed auditorium, they were honored with Lakota names during a ritual that tribal spokeswoman Danielle Finn said, “is a very special rite of passage for a Lakota person.” While standing on a bison pelt, the siblings were smudged with sacred grasses, presented with traditional quilts and eagle feathers, and given names associated with their White Mountain family.

Kyrie Irving’s Lakota name, Hela, is roughly pronounced (HAY’-law) and means “Little Mountain.” Asia Irving’s name, Tatanka Winyan, (tuh-TONG’-kuh WEE’-yun) means “Buffalo Woman.”

The Irvings’ late mother, Elizabeth Ann Larson, was a member of the tribe and lived on the reservation until her adoption at a young age. Their late grandmother and great-grandparents also have ties to the reservation.

The siblings were greeted by hordes of fans, many wearing green T-shirts with the Standing Rock Sioux seal, Kyrie Irving’s uniform number, 11, and the words “Welcome Home Kyrie Irving.”

“It truly is a good day for Standing Rock,” tribal Chairman Mike Faith said, turning to the Irvings. “For you two, welcome home.”

Many in the crowd, including Char White Mountain, consider the siblings to be part of their family.

“We want him to know who his relatives are,” she said. “We definitely don’t want him to think we’re people using him for his money. He’s family.”

Kyrie Irving discussed his Sioux heritage during a January 2017 interview with ESPN, saying “there’s a home connection” with the tribe’s pipeline struggles and that he wanted to have a legacy outside of basketball.

Irving this year asked Nike to put Standing Rock’s seal on a new sneaker. He also has a tattoo of the Standing Rock logo on his neck.