Defoe, whose own place in Capello's World Cup squad is far from guaranteed, insists King should be included for this summer's Finals.
"You know what you are going to get from Ledley," Defoe told the Daily Mirror. "He was excellent at Euro 2004. His mere presence on the pitch for us Spurs players during our bid for Champions League football has helped us to some superb results.
"At a World Cup there is always one game where the opposition has a special player who needs to be stopped. Ledley can do that job if he is there. We need to think about that.
"Ledley is a special player and if there is a chance that he could make the difference in a big game then we should take it."