The £1.5m TV campaign, created by Propaganda, will feature McGuinness in a series of light-hearted TV spots, showing him unable to resist the range of savouries on offer at Greggs.
The campaign breaks during ITV1's Hell's Kitchen on September 3, and carries the strapline: "Greggs the bakers ready when you are."
The six-week push will run nationwide on ITV1, Channel Five and multi-channel stations, alongside radio ads, online activity and point-of-sale material.
Scott Jefferson, marketing director at Greggs, said: "Paddy has proved to be a very popular character, and appeals to Greggs customers both young and old. He is extremely personable and brings just the right amount of humour to the campaign.
"It's been particularly pleasing to see that not only have we reinforced our appeal with existing Greggs customers, but by highlighting the wide range and high quality of the products available, we have been able to attract new customers as well as reigniting interest among shoppers who may have previously moved away from the brand."
The campaign will focus on Greggs' savoury range, including a new Cheese and Onion Pasty variety free from hydrogenated fats, artificial flavourings and colourings.
Media planning and buying was through AW Media and PR is being handled by Golley Slater.
This article was first published on brandrepublic.com