The mobile operator has signed a ground-breaking deal with Sony BMG to make available videos from dozens of popular recording artists, including Alicia Keys, Mark Ronson and the Ting Tings.
Before and after each music video, 3 will run a series of 20-second TV-style ads targeted according to the subscriber's age and demographic profile.
The deal marks a major step forward for 3UK's advertiser-funded content strategy, which it launched last March in partnership with Rhythm New Media. Brands including BMW, Microsoft and Pepsi have experimented with the service, but a lack of inventory has prevented it from reaching its full potential.
The mobile operator intends to aggressively target advertisers for the service, which it claims has already been used by 1.4m of its 4m UK customers.
It is keen to capitalise on the growth of mobile marketing, which is beginning to gain traction among UK brand-owners, according to a report from Enders Analysis. However, the research firm also warned that low levels of mobile internet use are making it hard for advertisers to reach the mass of consumers.
The launch of Apple's iPhone last November has helped raise awareness of mobile marketing. eMarketer forecasts that worldwide mobile marketing and advertising spend will reach £8.5bn by 2012, up from £1.4bn last year.