An Instagram post by KSI promoting JD Sports has been banned.
The YouTuber, who has an Instagram following of over 12 million, posted a video set to music of himself and others at a bowling alley in November.
The video included close-up shots of trainers and a shot of KSI - whose real name is Olajide "JJ" Olatunji - bringing attention to his shoes.
Others in the ad were seen wearing branded sportswear.
The video then ended with a shot of the JD Sports logo under text that said: "King of the Game."
The post was also captioned and said: "Head over to the @jdofficial YouTube channel to watch the full length film #kingofthegame", and tagged "jdofficial" and "@adidasoriginals".
JD Sports has said that viewers would have known it was an ad and it did not need to be labelled as such.
KSI had been contracted to post ads on behalf of the retailer and the ad had been produced with its approval.
The influencer told the Advertising Standards Authority that he believed the references to JD Sports in the ad made it clear to consumers that the video was an excerpt from a TV ad in which he had featured.
But after receiving a complaint, KSI included #ad in the post's caption in order to "mitigate any risk of consumers being misled".
The ASA said it welcomed KSI's "assurances" that the post had been amended but said it was still not "made clear" at the time the post was originally seen.
It added: "We welcomed Mr Olatunji's assurances that the post had been amended to include #ad.
"However, at the time the ad was originally seen, the commercial intent behind the post was not made clear upfront and the ad was not obviously identifiable as such.
"We therefore concluded that it breached the Code."
The ASA also advised both JD Sports and KSI to make sure their future ads were "obviously identifiable".
"We told JD Sports and KSI to ensure that in future their ads were obviously identifiable as marketing communications and made their commercial intent clear upfront, for example, by including a clear and prominent identifier such as #ad," it added.
The 29-year-old is also known as a boxer, rapper and the founder of Prime energy drinks.
Earlier this year, the internet star apologised to viewers for using a racial slur in an online video.
The clip drew outrage on social media and was later removed from the Sidemen channel, a series of YouTube pages belonging to several British internet personalities.
KSI addressed the situation after the backlash at the time and tweeted: "I wanna apologise for saying a racial slur in a recent Sidemen video.
"There's no excuse, no matter the circumstances, I shouldn't have said it and I'm sorry.
"I've always said to my audience that they shouldn't worship me or put me on a pedestal because I'm human.
"I'm not perfect, I'm gonna mess up in life, and lately, I've been messing up a lot. So I've decided I'm gonna just take a break from social media for a while."