Tindall, DDB's head of art, joins the agency's other three creative partners Paul Weinberger, Jason Lawes and Sam Cartmell with an equity stake. However, Fisher, DDB's head of account management, will not receive equity. Fisher will be responsible for the day-to-day management of the 60-strong agency and will oversee the £60 million Tesco account.
The agency initially offered the managing director's post to Mark Cadman, but he turned it down in favour of the chief executive's job at Euro RSCG at the start of the year.
Hammersley said: "That someone of Justin's calibre is joining us as creative partner reflects our real commitment to putting creativity at the top of the agenda and his desire to be part of that. He is one of the most awarded creatives of his generation in the world and has a real sense of where this business is headed."
He continued: "I worked closely with Karen at DDB in 2004 and 2005. She's a fantastic talent and a delightful person. After six months we now employ 60 people and we really need some help in running the place. The combination of Justin and Karen is fantastically exciting."