Garland is planning to take five months off to travel the world with his family, prior to launching a new business venture in the world of content and brands in 2007.
According to the company, it is a move that has been in the planning for several months.
Productions made by 19 include 'Pop Idol' and 'World Idol', sponsored by Kit Kat, and 'American Idol', which included heavy product placement by soft drinks manufacturer Coca Cola.
The company creates bespoke television content for worldwide brands including Procter & Gamble, PepsiCo, Nokia and Adidas. It operates in more than 30 markets worldwide and is a global leader in the integration of brands with entertainment properties.
Garland said: "It has been a joy to work with Simon and the whole team at 19 and see the company develop in the way that it has. I have no doubt that it will continue to grow and prosper but to take time out with the family and travel is a once in a lifetime opportunity, before launching a new business next year."
Fuller said: "It has been great working with Charles over the years. He has some great ideas and we wish him all the best in his new venture. I am looking forward to us partnering on projects together."
Last month, 19 Entertainment announced the acquisition of advertiser-funded content production company Freedom Media for an undisclosed sum.
Robert Dodds, the founder of Freedom Media, took the role of president of 19 Entertainment, with responsibility for the day-to-day running of the broadcasting content and talent management firm.
19 Entertainment properties also include promotion for David and Victoria Beckham, Honda F1 Racing, and the Elvis Presley Estate.
In March, former Universal McCann executive vice-president Chris Shaw joined the company to head promotion of the Honda F1 Racing team.
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