Outside, Prince Carlos's birthday celebrations this week appeared jovial, an important landmark for the monarch-to-be, marked by splendid and famous parties.
But inside, the real observers say that the occasion for Charles to be a little poignant, as he prepares for a life even more busy than he knows, and a less charitable work and opinion.
In fact, only last week, in an intimate interview with the BBC, the prince asked him if his unbridled opinions would continue when his reign as king began.
"No, it will not. They are not so stupid," he replied.
MANUFACTURE OF A KING
Theoretically he became an apparent heir in 1952 when he was three years old (although a regent would serve if his mother had died before reaching adulthood) and was in the shadow of Queen Elizabeth II all adulthood.
Sixty-seven of his 70s were spent preparing for the role of King.
"It reaches the age where most people are thinking about retiring," said the royal biographer Penny Junor.
"Some people of the 70 are already in the homes of the old people and are slowing down … He has not yet obtained the position that he was trained."
The queen's relationship with her son was not the closest, and Mrs. Junor said that Charles would be moved by her host for a birthday party for him.
"He loves his mother but is not close," he said of his relationship.
"I think probably the problem was, when I was a child, I was juggling being the queen at an early age for being a girl too.
"It was unthinkable at that time that his children should take her when she was on foreign trips."
While Charles watches her mother, Mrs. Junor said that there was never a "large amount" of heat between the couple and that Queen, 92, acknowledges that there is very little he does not know.
"What would you say? You are 70," said the biographer.
"There is not much that a mother can say at age 70.
"He saw state roles, he met with prime ministers.
"But he was watching him.
"It will be the best prepared monarch that this country had."
Editor in chief of Magazine of the Mafia and the real author Ingrid Seward said that Charles knew that he was destined for the crown all his life.
"It's what was prepared to be, it's just that it's been too late," he said.
"He told him in the past that he does not want to think about it, when his mother is no longer."
WORK OF CHARITY AND WHICH IS SUPPORTED APOLITHIC
Once the Prince becomes a king, he will not have so much time to dedicate himself to his beloved charities.
For 40 years, Charles has supported many philanthropic causes, including his own charities. The Prince's Trust Group and the Prince of Wales Charitable Fund.
He really enjoyed his charities, but in 1987 he said he always felt he was rushed.
"The problem is that I always feel that unless I hasten to do things and trying to help them furiously, I will not (and not the monarchy) be relevant and will be considered a simple playboy," he wrote in a private letter.
He has also earned a reputation for being politically false about issues such as climate change, environmental conservation and Islam.
It is these controversial opinions that the real commentator Claudia Joseph believes that Charles will have to repress when he becomes king.
"He is known to write many letters to government ministers and to press them on their domestic interests, such as the environment, but is expected to be apolitical when he is a monarch," he said.
"You will have to drive a more cautious way."
Ms Seward said that the Prince was "long before his time."
"I notice that a few years ago (princess), Diana, telling me that Charles would not let him use his hair more because of the ozone layer," he said.
"People say that he has old views but I think he's thinking a lot."
In spite of its variety of beneficial achievements – that their children, Prince William and Prince Harry, are now now pursuing rigorously – Queen rarely praised her child in public.
Miss Junor said that the Prince never felt that he was good enough for his mother or his father, Prince Philip.
"This is part of Charles's problem in life, he has no great confidence in himself," he said.
"I think he now has more confidence since Camilla (his second wife).
"I think it was man's man.
"It will be the force behind the throne".
A DUQUESA DE CORNWALL
Although the couple was married for 13 years, the "anti-Camila" feeling is still palpable in Britain due to the great love of the country by Princess Diana, Carlos's first wife.
"There is still a feeling that they (Britain) do not want Camilla to be Queen," said Seward.
"When this happens, people will only accept it completely."
The couple lives in Clarence House in London and goes to real domestic and international commitments, such as a recent visit to Ghana and Nigeria on a real tour.
Royal author Robert Jobson wrote in his new book, Charles to the seventy: thoughts, hopes and dreams, that Camilla will become Reina once her husband ascends to the throne, although Clarence House issued a statement when the couple married her.
That statement withdrew calmly from the royal family website earlier this year.
Charles was also supported by the leaders of the Commonwealth nations at the CHOGM event in London earlier this year to be the new chief of the Commonwealth when he eventually assumes his mother as a monarch.
A KING OF THE CHANGE
While the new monarchy will not bring immediate changes, Mrs. Junor said the changes would come under a king of Carlos.
"If Carlos did everything he did to the Queen, that would be quite wrong," he said.
"I think that William (the eldest son of Charles) will bring something completely new again.
"They are not radically new, but they learn from each other and understand what works."
Ms Seward accepts that the change is inevitable.
"I know he (Charles) wants a worn monarchy," he said.
"You will be concentrated in your children and I think of your family."
She doubted that Carlos would be as popular as Queen Isabel, who promised as a 21-year-old princess to serve her people until she died, and discarded her abdication in favor of her son.
"I do not think anyone is as loved as the Queen," Seward said.
"Many people never knew anything else.
"I think that he (Carlos) will make a very good king, when it comes to, it comes."