Image copyright Reuters Image caption Colin Kaepernick was a quarterback for the San Francisco 49ers for six years

An American football star who sparked a furore by kneeling during the national anthem has been unveiled as one of the faces in a major advertising campaign.

Former San Francisco 49ers quarterback Colin Kaepernick is appearing in Nike's "Just Do It" 30th anniversary campaign.

In 2016 Kaepernick refused to stand for the anthem in protest at police violence against African-Americans.

Other players followed suit but the protest has divided the country and sparked Donald Trump's anger.

The US president has called players who "disrespect" the US flag "sons of bitches" and called for them to be sacked.

Kaepernick has not played in the National Football League (NFL) since last year, and is suing the organisation, arguing team owners deliberately froze him out because of his activism.

The Nike adverts show Kaepernick with the slogan: "Believe in something. Even if it means sacrificing everything."

Media playback is unsupported on your device Media caption Why America's sports stars began to take a knee

Kaepernick is one of a number of sports stars, including fellow NFL players Odell Beckham Jr and Shaquem Griffin, to appear in the 30th anniversary "Just Do It" campaign.

On Monday the star posted the advert and the slogan on his Twitter account.

Gino Fisanotti, Nike's vice president of branding for North America, was quoted by cable sports network ESPN as saying: "We believe Colin is one of the most inspirational athletes of this generation, who has leveraged the power of sport to help move the world forward."

One of the other stars of the Nike campaign, tennis great Serena Williams, expressed her support.

Some on social media though have been using the #BoycottNike and #JustBurnIt hashtags, a play on the company's slogan. Country star John Rich posted a photo of a pair of socks with the Nike emblem cut off.

Kaepernick, 30, remained on a contract with Nike throughout the kneeling row, but it has now been renegotiated to make him part of the anniversary campaign.

In May this year, the NFL announced that teams whose players who knelt for the national anthem would be fined under a new policy.

The league said players not willing to stand for The Star-Spangled Banner could stay in the changing rooms until it had been performed.

However the new policy is yet to be imposed as negotiations between the league and the players' union are ongoing.

Image copyright Getty Images Image caption The on-field protests began in 2016 and divided the country

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