However, Grant was dismissed last month after failing to lead the Blues to either Premier League or UEFA Champions League glory.
He has now taken charge of Greek club Panathinaikos on a two-year contract.
Jose Peseiro resigned as Pana coach in May and Ten Cate is delighted to have been brought in as his replacement.
"In my career I have been used to working at the highest level of competition and that's one of the reasons why I consider this new step to be a great challenge," Ten Cate told Panathinaikos' official website.
"Panathinaikos' organisation, history, ambition and attitude towards football in general match those of the greatest football clubs in Europe."