Dad is relieved upon seeing his son.
Prince Harry, 23, a second lieutenant in the Household Cavalry, was flown out from Helmand Province under orders from the Chief of Defence Staff.
The prince's deployment was subject to a news blackout in a deal struck between the MoD and newspapers and broadcasters in the UK and abroad.
The agreement broke down after the story appeared on influential American website The Drudge Report.
Prince Harry was sent secretly to Afghanistan in December but was ordered out of the country by defence chiefs on Friday.
Prince Charles said he had found it "quite difficult" to keep the secret.
"People kept saying to me 'you must be so frustrated about Harry not being able to serve abroad'" He said when he was asked where Harry was, he'd reply: "He's on exercise somewhere."
The Prince of Wales said he was now more aware of the stresses and worries of families with loved-ones serving in places like Iraq and Afghanistan.
"We owe an enormous amount to those families of servicemen who endure so much and support their loved ones with such understanding. It makes a huge difference," he said.
"I also feel very strongly that we don't often appreciate what the people in the armed forces are doing, putting up with the most impossible conditions, very often in hazardous circumstances in heat or freezing cold, being shot at or rocketed at and goodness knows what else."
He said all armed service personnel were owed "an enormous debt of gratitude for performing their duty".
Finally Prince Charles said: "I've been incredibly proud of Harry and I promise you, equally proud of all the dedicated service given by all our armed forces."