The ad will go live online before airing on TV from 1 April.
It shows Wallace watching a high-energy consumption multiple-screen TV that he has invented and goes on to show Gromit getting advice from Npower customer care advisor Penny on how to cut energy consumption by using a smartpower monitor.
Npower will distribute the ad to its customers through an email campaign on Thursday (18 March) to drive traffic to a site that allows people to view it through a Wallace-style TV or normal widescreen.
An Npower spokesperson says it is using social media and bloggers for the first time to “create a buzz and excitement before the ad goes on TV, and encourage interaction with the brand”.
The 30- and 40-second TV ads, created by Aardman Animations and VCCP, will run until May.
Npower is also launching an online competition giving away low-energy eco TVs and laptops to encourage people to share the video online.
The TV campaign is the first to include the new Npower logo, which the energy supplier revealed on Tuesday (16 March).
Npower also confirmed this week that it is to replace Coca-Cola as the sponsor of the Football League in a £21m three-year deal.