Bartlam will be responsible for producing all the TV, film and content Iris creates for its clients, such as Adidas, Britvic, Domino's and Mini. She will lead a team of more than 30 people.
She will report to Dan Saxby, the chief executive, London at Iris, and the executive creative director, Chris Baylis, who joined Iris at the start of the year from Tribal Worldwide London where he had the same role.
Prior to joining Havas Worldwide London in May 2013, Bartlam was the managing director at the production company Cut & Run from 2012. She was previously head of television at Adam & Eve from 2008 until shortly after its merger with DDB London.
Saxby said: "We continue to invest in world-class talent. Leila brings a wealth of experience, passion and a reputation for cutting-edge ideas and delivery, and will be a strong leader to our existing film and content team."