The 29-year-old Tottenham Hotspur defender, who suffers from a chronic knee injury that prevents him from training, is set to play alongside John Terry in central defence when England meet the United States in their opening Group C game on June 12.
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"If I play, it would be my first World Cup appearance," he said on Sunday. "And for me that would be a dream come true, of course.
"It's something that you envision as a young player - to play for your country at the World Cup - and, yeah, it would be a dream.
"But right now I am just part of a 23-man squad and I am trying to work hard and prove that I can be part of a winning team."
King's England career has been sporadic, hit by injuries and punctuated by disappointments that included his enforced withdrawal from the 2006 squad with a broken foot bone.
His club manager Harry Redknapp said: "There's no cure. There's no cartilage, nothing to operate on. It's just bone on bone. So it's just a question of managing it ..."
Instead of playing, however, King worked with his club's medical staff to find a way of strengthening his knees and preserving his career, a decision that has paid off.
Capello promised to keep King in his thoughts and when he proved his fitness in successive important games for Tottenham, he was picked for England's provisional 30-man squad, scored a goal in a warm-up game against Mexico and retained his place in the final 23.
"Just being here is great for me," he
