Donald Trump and LeBron James once again find themselves on opposing sides of a national debate as the fallout from Nike’s decision to make Colin Kaepernick the face of its new ad campaign continues.

While Nike’s share price fell 2% on Tuesday, there’s little doubt the campaign is generating huge publicity: according to ESPN, Nike was mentioned 3.4m times on Twitter in the 21 hours after Kaepernick first mentioned the advert. The commercial will air on television for the first time on Thursday night during the NFL’s opening game between the Philadelphia Eagles and the Atlanta Falcons. The ad will be narrated by Kaepernick and will also feature Serena Williams, NFL star Odell Beckham Jr and marathon runner Eliud Kipchoge.

Kaepernick started kneeling during the anthem before NFL games two years ago. The quarterback’s protest against racial injustice has since spread throughout the league and last year Trump said that any player who knelt during the anthem was a “son of a bitch” and should be fired.

After saying Nike’s campaign sent a “terrible message” on Tuesday, Trump doubled down in a tweet on Wednesday. “Just like the NFL, whose ratings have gone WAY DOWN, Nike is getting absolutely killed with anger and boycotts,” wrote the president in a tweet. “I wonder if they had any idea that it would be this way? As far as the NFL is concerned, I just find it hard to watch, and always will, until they stand for the FLAG!”

Trump was presumably referring to videos on social media of people burning their Nike products in protest at Nike’s campaign. While the president is correct that the NFL’s audience has fallen, it is in line with a general decline in television viewership in America. Very few NFL players continue to kneel for the anthem – in the second week of preseason only one of the league’s 1,664 players did so.

Many athletes have spoken up in support of Nike’s campaign. James, arguably the most famous athlete in America, said: "I stand with Nike, all day, every day." The president and James have clashed in the past. In September 2017, James called Trump a “bum” for rescinding his invitation to the Golden State Warriors to celebrate their NBA title with a visit to the White House. Last month Trump attacked James on Twitter after the Los Angeles Lakers star was interviewed by CNN’s Don Lemon. Trump wrote that Lemon “made Lebron [sic] look smart, which isn’t easy to do”, after the two discussed Trump’s history of attacks on African American athletes.

Williams, who like James is sponsored by Nike, also supported the campaign. "Having a huge company back [Kaepernick], could be a controversial reason for this company but they're not afraid and I feel like that was a really powerful statement to a lot of, a lot of other companies," Williams said on Tuesday.