Paul Cohen joins McCann as creative partner from AMV BBDO, while Olivia Johnson becomes planning partner from Hooper Galton where she held the same role.
Prior to AMV, Cohen worked at Mother where he worked on brands including Orange, Coca Cola, Time Out, Kiss FM and Selfridges. He also set up creative agency The North Terminal.
Simon Learman and Brian Fraser, joint executive creative directors at McCann London, said: "Attracting a major talent like Paul illustrates both how far we have come and how far we want to go. We're extremely ambitious and Paul adds tremendous bandwidth to our department at what is a very exciting time for us."
Johnson has previously worked for Ogilvy where, as global planning director, she worked on Unilever's Dove Campaign for Real Beauty, overseeing its global roll-out.
Nikki Crumpton, chief strategic officer at McCann London, called Johnson a "fantastic appointment", and highlighted her "wealth of experience from both large and smaller agencies across big global brands and smaller domestic clients".
Earlier this month, L'Oreal-owned brand The Body Shop appointed McCann London to handle its global advertising account. It won the account after a pitch against undisclosed agencies, which was overseen by Philip Clough, the retailer's global brand and innovation director.
McCann London's first work for the brand is expected to appear later this year.