Thomas became a household name in the US after he began starring in his own commercials in 1989. His back-to-basics, homely image -- always wearing a short-sleeved white shirt and red tie -- has become one of the longest-running and enduring advertisement campaigns in history.
A cause of death was not given, but Thomas had undergone major operations in the last five years including kidney dialysis, a quadruple heart bypass and gall-bladder surgery.
Thomas made his millions in 1968 working for Kentucky Fried Chicken, after establishing four restaurants for Colonel Sanders in Colombus. He set up his own restaurant in Columbus the next year and named it after his daughter Melinda Lou, nicknamed Wendy.
By 1996, Wendy's had grown to more than 5,500 restaurants in 34 countries and in the same year bought Canada's Tim Hortons chain of coffee shops and bakeries.
In 2000, Wendy's signed an exclusive deal for Thomas's name, voice and likeness, so the commercials can continue.
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