Stevie Wonder took a knee in support of embattled U.S. sportsman Colin Kaepernick while performing at the Global Citizen Festival on Saturday (23Sep17).

Kaepernick's contract with the San Francisco 49ers was not renewed this summer (17) and he remains a free agent after sparking a backlash for kneeling during the U.S. National Anthem at games last year (16) to protest discrimination against his fellow African-Americans.

On Friday (22Sep17), U.S. President Donald Trump hit out at Kaepernick and other athletes who have opted to kneel in support of the football player, telling a crowd of supporters in Alabama they should be let go from their teams.

"Wouldn't you love to see one of these NFL owners, when somebody disrespects our flag, to say, 'Get that son of a b**ch off the field right now. Out! He's fired'," he said.

He followed up his controversial comments on Saturday on Twitter, writing, "If a player wants the privilege of making millions of dollars in the NFL,or other leagues, he or she should not be allowed to disrespect our Great American Flag and should stand for the National Anthem. If not, YOU'RE FIRED. Find something else to do!"

Following his comments, President Trump received backlash from celebrities and athletes and when Wonder took the stage to perform in New York he showed his support by kneeling.

"It is only through life we can make life happen through ourselves and each other," he told the crowd. "Our global brothers and sisters, I didn't come here to preach, but I'm telling you, our spirits must be in the right place all the time."

"I'm taking a knee for America - not just one knee, but both knees in prayer for our planet, our future, and leaders of our world," he added.