Nike has become the first company in the UK to have an advertising campaign on Twitter banned.
The Advertising Standards Authority said that tweets by of Wayne Rooney and Jack Wilshire to promote the campaign were not clearly labelled as adverts.
The 'Make It Count' campaign featured athletes making commitments at the start of the year to make the most of their skills.
Wayne Rooney, with more than 4m followers, said in a tweet: "My resolution -- to start the year as a champion, and finish it as a champion...#makeitcount gonike.me/makeitcount"."
Wilshire tweeted: "In 2012, I will come back for my club -- and be ready for my country.#makeitcount gonike.me/Makeitcount".
Nike said that the athletes were known to be sponsored by Nike, and that they were simply allowed to tweet support for the campaign "at their own discretion".
But the ASA received a complaint about the ads, and decided that the messages were "agreed with the help of a member of the Nike marketing team".
It said: "We considered that the Nike reference was not prominent and could be missed, consumers would not have already been aware of Nike's "£makeitcount" campaign and that not all Twitter users would be aware of the footballers' and their teams' sponsorship deal with Nike.
"We considered there was nothing obvious in the tweets to indicate they were Nike marketing communications."
The ASA suggested Nike and other marketers said the ads could not appear again, and could have included '#ad' to indicate they were paid for by Nike.