Stickler will report to chief strategy officer Zaid Al Zaidy and Erika Darmstaedter, global business director for Mars. Stickler will lead the global strategy for Whiskas and head up the strategy for Mars-owned brand Twix.
Prior to joining TBWA\London, Stickler worked at 23red as head of strategy and planning. She previously worked at Publicis as the global brand director working on brands including Minute Maid and Coca-Cola.
Stickler has also worked as a board account director at Euro RSCG and Rainey Kelly Campbell Roalfe/Y&R.
Al-Zaidy said: "Carol is perfect casting for TBWA\ and our culture of disruptive ideas and end to end branded experiences. As a seriously accomplished senior planner and a lovely person, Carol brings with her 'friendly gravitas' and, critically, a love of chocolate and cats."