Colin Kaepernick, the former San Francisco 49ers quarterback, took part Thursday in the annual Unthanksgiving Day on Alcatraz Island.

The San Francisco Chronicle reported that Kaepernick made a surprise appearance at the event, which commemorates the 19-month occupation of the prison by Native American activists from 1969-1971.

“Our fight is the same fight,” Kaepernick told the crowd, in a message he posted on Twitter. “We’re all fighting for our justice, for our freedom. And realizing that we are all in this fight together makes us all the more powerful.”

The 89 activists who occupied the prison almost five decades ago demanded that it be turned into an American Indian cultural center and school.

During the commemorative event, called the Indigenous People’s Sunrise Gathering, the crowd gathers on the island to watch the sunrise on San Francisco Bay.

“It’s about reflecting, remembering and celebrating that we are still here and our culture still survives,” Michael Horse, a Native American actor, told Newsweek.

Kaepernick, who was recently named GQ's 'Citizen of the Year,' began kneeling instead of standing during the national anthem last season to protest racial inequality and police brutality. The demonstration sparked a wave of NFL protests by players during the anthem that repeatedly have been denounced by President Trump. Kaepernick parted ways with the 49ers in March and hasn't been signed by another team.

The Associated Press contributed to this report