Vegan musician Stevie Wonder joined the #takeaknee protest yesterday, before his performance at the 2017 Global Citizen festival in New York.
Wonder, who was helped to his knee by son Kwame Morris, said: "Tonight, I’m taking a knee for America.
"But not just one knee; I’m taking both knees.
"Both knees in prayer for our planet, our future, our leaders of the world and our globe. Amen."
The #takeaknee protest was initiated last season by San Francisco player Colin Kaepernick.
The quarterback knelt during the anthem as a move to bring attention to police violence against African Americans - a move that has been adopted by a number of National Football League players.
The protest hit the headlines in recent days after US President Donald Trump spoke out angrily about it during a rally in Alabama, saying: "Wouldn’t you love to see these NFL owners, when somebody disrespects our flag, to say: ‘Get that son of a b—- off the field right now, out. He’s fired. He’s fired!"
But his outburst earned criticism from a slew of players and NFL Commissioner Roger Goodell.