Clear Channel secured the contract to sell the advertising on VMG Global's portrait digital screens in August and the addition of Festival Place and Frenchgate brings the network to 120 screens.
Advertisers which have used the network include Coty Prestige, Kellogg's, Unilever, COI, Vodafone, Johnson & Johnson, American Express and Lloyds TSB.
The 65" high-definition, full-motion screens are positioned at major walkway intersections and feature an interactive store guide and map to help shoppers find their way around the two shopping centres.
Rob Atkinson, managing director at Clear Channel Outdoor UK, said the quality of the screens, their location within the malls and the footfall within the malls makes the network a highly desirable proposition for advertisers.
"We look forward to substantially expanding the network over the coming months," he added.
In August Dominic Brookman, chief executive of VMG Global, acquired the contracts of collapsed digital outdoor outfit Vision Media Group International, of which he was chief executive, from the administrator.