Caulker scored in England's defeat to Sweden last night.
"Having been there myself, it’s a big confidence booster when you first go into the England squad,” said King, who won the first of his 21 caps in March 2002. “You come back to your club with your head held high. You’re so confident and you really believe you are a player.
“It was a brilliant feeling and it will be beneficial for Tottenham when Steven wins that first cap. He has been fantastic.
“He has slipped into the team seamlessly and is so composed for one so young. It’s brilliant for him that he has been called into the England squad.”