Barbella will oversee the Microsoft/Nokia business. He was previously the executive creative director at DDB Spain, where he handled clients including Audi, Volkswagen and Movistar.
Most recently, Barbella has freelanced at agencies including Lola, BBDO Spain and FCB Chile.
Ball joins JWT after five years at Bartle Bogle Hegarty, where he worked across Barnardo’s, British Airways, ITV and Johnnie Walker.
Ball began his career at CHI & Partners copywriting for brands including Tango and Typhoo. He subsequently moved to Publicis London, where he handled accounts including Cadbury and Procter & Gamble.
Russell Ramsey, the executive creative director at JWT London, said: "Fernando and Alex are very talented and very nice people. I am delighted to have them on board."
JWT London won The Arden Award at the Campaign Big Awards in October for its work on the Android KitKat operating system.