The agency has brought in Joe Sinclair, the co-founder of Burson-Marsteller's consumer shop Be More, to be creative director.
It has also hired Gemma Hopkin as planning director from Frank PR, where she has been a board director for seven years.
Sinclair spent three years at Burson-Marsteller, where his work included the '2 minute silence' campaign for the Royal British Legion.
He said that his new role would be split equally between advising existing clients and developing new business.
He added: 'Agencies are recognising the need to up our game creatively, and Citizen is getting ahead of the curve on that.'
At Frank, Hopkin led the relaunch of Premier Inn and worked with clients including KitKat and Hovis.
She reunites with Citizen Relations CEO Frankie Cory, who left Frank in late 2011. Cory described the hires as 'the start of an exciting new era.'