The ad, created by Mother, is part of a multimillion-pound brand campaign for Diet Coke which focuses on fashion and gossip, revealed by Marketing (16 February).
The spot features three female puppets called Eleanor, Bernadette and Irene, who, according to the company, "encapsulate the 'Love it light' spirit". A series of 10-second ads will also air from late April
The push is supported by a Diet Coke Facebook hub, a year-long partnership with online fashion retailer ASOS.com, and a tie-up with Kiss radio.
The ASOS.com deal centres on an on-pack promotion, which broke last month. Consumers have the chance to win an outfit every 30 minutes, as well as money-off vouchers that can be redeemed via the Coke Zone loyalty site, handled by Carlson Marketing.
Consumers who purchase 2-litre bottles and fridge packs of Diet Coke will also be able to obtain copies of Bauer Media magazines Heat, Grazia, Closer and More! via the Coke Zone.
Cathryn Sleight, marketing director for Coca-Cola Great Britain, said: "The TVC execution perfectly represents what diet Coke stands for and talks to our drinkers in a light-hearted and uplifting way."
She added: "The aspirations, personalities and views of our three girls mirror those of the modern-day diet Coke girl – we love them and hope our audience does too. Fashion, femininity and fun is at the centre of our brand and this is reflected in all 2010 activity."
In 2009, sales of Diet Coke were up 5% year on year, to £421m.