Pop star Katy Perry has come under fire from members of various consumer advocacy groups for appearing to promote Pepsi soda by working with brand officials to advertise her new album.

Campaigners from six different organisations, including the Center for Science in the Public Interest and the California Center for Public Health Advocacy, teamed up on Tuesday (22Oct13) to place a full-page ad in entertainment industry publication Variety.

The page features an open letter addressed to the Roar hitmaker, and reads in part: "Virginia Slims and other tobacco companies used glamorous celebrities and models to position smoking as hip, sexy and rebellious. Today soda companies are using you and other celebrities to convince young people that drinking soda is hip, sexy and rebellious. 'Drink Pepsi and you can be cool like Katy Perry,' is the takeaway message for your young fans. 'Live for now' and worry about the health consequences later."

The activists go on to urge Perry, who does not have an endorsement contract with Pepsi, to turn her back on the brand, which recently sponsored a fan competition to help decide which single the star should release next.

The letter continues, "Kids love you, Katy Perry. You count many millions of teens and tweens among your 'KatyKats' (fans). Their devotion to you has brought incredible commercial success and wealth. But being popular among children brings with it an enormous responsibility. Don't exploit that popularity by marketing a product that causes disease in your fans."

Perry has yet to respond to the ad attack, although a spokesperson for Pepsi has denied targetting kids by working with the singer.

Pepsi representative Andrea Foote tells USA Today, "We have a long history of responsible advertising and marketing practices, including a commitment to not direct our advertising to audiences comprised predominantly of children under 12."