Discussing Caulker's inclusion in the starting lineup, 21-capped King has backed the Spurs man to improve as a player for the experience.
"Having been there myself, it is a big confidence booster when you first go into the England squad," King told the London Evening Standard. "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."
King retired from playing at the end of last season following a large number of knee injuries.