Golf great Tiger Woods joined the growing list of athletes to come out in support of Nike's newest ad featuring former San Francisco 49ers quarterback Colin Kaepernick.

Nike this week unveiled the latest 'Just Do It' campaign starring NFL free agent Kaepernick, with one image reading: "Believe in something. Even if it means sacrificing everything."

The campaign has split opinion in the United States, with Kaepernick first sitting and then kneeling during the playing of the national anthem before NFL games starting in 2016 to protest police brutality and racial injustice in the country.

But 14-time major champion Woods praised Nike for making Kaepernick as the face of its 30th anniversary 'Just Do It' campaign.

Speaking after Friday's second round of the BMW Championship, where he is five shots off the pace, Nike athlete Woods said: "It's a beautiful spot.

"I think Nike is trying to get out ahead of it and trying to do something special, and I think they've done that.

"It's a beautiful spot and pretty powerful people in the spot."

Nike received both praise and criticism after the ad, narrated by Kaepernick, aired during the third quarter of Thursday's NFL season opener between Super Bowl champions the Philadelphia Eagles and Atlanta Falcons.