LOS ANGELES: In the Diet Coke advert, the singer can be seen singing while cycling through dark streets and into a store, before returning to her concert.

The Advertising Standards Authority (ASA) said 18 viewers complained because Duffy was not wearing reflective clothing and her bicycle had no lights.

A further four people complained the ad was irresponsible because children might copy her behaviour.

The company argued that the ad was not meant to reflect reality, but rather "Duffy's fantasy, a scenario that depicted her escape from the pressures of stardom and far removed from the real world".

The ASA agreed and said children would understand cycling round a supermarket was not a realistic situation.