McCann and JWT London are both on the roster for Premier Foods, which owns brands including Mr Kipling, Homepride and Bisto.
Within the advertising roster JWT London was responsible for Mr Kipling but, following a rejig that took place earlier this year, McCann now holds that account. JWT remains on the Premier Foods roster.
McCann’s campaign introduces a new strap line, "an exceedingly good distraction", and begins with a 30-second TV ad in which a couple distracts their party guests with Mr Kipling’s French Fancies after a lewd snap appears in their honeymoon slide show.
Alex Lubar, McCann London’s chief executive, said: "Mr Kipling is an iconic component of our nation’s snacking.
"We’re delighted to have been given the opportunity to work on this campaign, helping to build on the brand's recent success with the next stage of creative development."
The ad will first air on ITV on 11 April and is part of a £2.5 million campaign.
Premier Foods consolidated its eight key brands into JWT London and McCann London in 2012, when JWT was handed the Mr Kipling account along with others, and McCann added Batchelors and Bisto to its existing roster of Premier Foods brands.
JWT’s relationship with Mr Kipling goes back much further than 2012. In 1967 when Rank Hovis McDougall asked JWT how it might make more money from flour, the agency, led by Stephen King, helped create Mr Kipling as a brand. In the 70s, JWT created the "exceedlingly good cakes" strap line for the brand.
Over the years, numerous agencies have created advertising for Mr Kipling, including Saatchi & Saatchi, 101 and WCRS. McCann has even held the brand's advertising account before, winning the business after a competitive pitch in 2006.