Zeidler, who reports to managing partner Ben Whattam, will work across all the agency’s clients, including Bentley’s global advertising account.
Keko recently defended the Bentley business after repitching against MullenLowe London and Y&R London.
At Karmarama, Zeidler is credited with an instrumental role in winning and creating campaigns for Sony, Porsche and Grant’s, as well as working on award-winning work for Honda. He worked as a creative director at the agency for five years and previously spent six years at relationship marketing agency HS&P and then two years at Crayon, its sister digital shop, also as creative director.
Lines joined Keko in 2014 as creative partner but left the agency earlier this year to "pursue other opportunities", the agency said. He was formerly global creative director for Spark44, the global joint venture agency for Jaguar in which Jaguar Land Rover has a 50% stake.
Keko London launched in January 2013 as a sister agency to German agency Kemper Kommunikation.
Whattam said: "We’re very excited Paul is joining our story. We’ve got big ambitions and Paul is the perfect person to help shape and evolve our capability, and lead us into a new era of collaborative creativity with our clients".