Details of the activity are to feature on 20 million two-litre bottles and multipacks of 330ml cans of both variants. The campaign will target 11 to 16 year-olds and prizes will include flying to the US or Europe - to see singer Shakira live in concert or spending a weekend "living like Britney Spears - as well as the day with Gareth Gates.
"These three hugely popular music stars will appeal to our core teen audience and their mums, driving sales for retailers, said Karen Goffe, Pepsi UK's head of marketing.
The push will run until mid-September and has been devised by KLP Euro RSCG.
It comes as Britvic launches its new Pepsi Twist drink. A nationwide sampling campaign kicks off on 5 August in Sainsbury's and Safeway car parks. The campaign, also through KLP, will be targeted at 500,000 consumers and runs for four weeks. When a consumer purchases Pepsi Twist at participating outlets they can receive a free signed Gareth Gates photograph.