The multimillion-pound campaign, first aired during the Brit Awards on ITV this year, marked the Welsh singer's first outing as the new face of Diet Coke. In the ad she is seen cycling the streets at night singing a cover of Sammy Davis Jr's I Gotta Be Me.
The Advertising Standards Authority received 22 complaints that the ad either "condoned behaviour prejudicial to health and safety", because she was not seen wearing reflective clothing or using lights, or that it was irresponsible because children might copy her behaviour.
Coca-Cola said it carried out a "vigorous" assessment of highway code regulations. Duffy had been wearing a black and white sequined top that reflected light and gave her a "luminous glow" so that she stood out in the dark. The soft drinks company added that the bike had lights.
The authority said the cycling sequence was clearly "unreal and fantastical" and the ad was not shown around programmes children were likely to be watching.
Source: theguardian.co.uk/ YouTube