The Monegasque royal has an 19-year-old daughter, Jazmin Grace Grimaldi, whose mother is American, and a son, Alexandre Eric Stephane Coste, eight, by a Togolese flight attendant (pictured).
Neither have succession rights, but both will be looked after financially by their father, who is estimated to have a personal fortune of more than $1 billion.
Albert said so himself during a TV interview with Larry King in 2005.
It's not very often he talks about his children, but he responded to the interviewer's questions about the little boy.
"You know – and I've always said this, he will be very well taken care of," he said, adding: "He will have everything he needs and I will see him as often as possible."
News of the little boy's existence broke a month after the death of Albert's father Prince Rainier - while he was still in mourning.
The story appeared on the front of the French papers revealing that Nicole Coste (pictured above) - a former air steward originally from the west African nation of Togo - had a 22-month-old son by the prince.
"When an event like this that is strictly in the private realm and it concerns your private life when that is made public it's sort of a shock and you do feel betrayed in many ways," said Albert of his feelings when the news became public.
He adds: "I felt as though it would come out at some point."
When Larry asked why the story came out, Albert answered:
"I had already taken care and pledged support and had already started supporting. But I think the lure of recognition and being in the public eye was very appealing to her."
Alexandre lives with his mother, whom Albert met on a flight, in France. They share an estate provided and secured by his father near Monaco.
In this same interview, Albert responded to questions as to whether he had any other children, saying: "I don't know of any other case."
But eight months after the interview he issued a statement through his lawyer confirming he was the father to a second child – Jazmin.
He had planned to keep his relationship with the teenager a secret until she was an adult, he said.
But he came forward after increasing speculation about the identity of her father had been making life difficult for the little girl. She was then 14 at the time and living with her mother in California.
Tamara Jean Rotolo, a real estate agent, had a brief relationship with Albert in July 1991 while she was in Monaco. Her daughter was born roughly nine months later.
She filed a paternity suit which went to trial in 1993 but was thrown out by the judge, who deemed that – since the encounter happened in Monaco – and because there was insufficient contact between Albert and the State of California, the court had no jurisdiction.
A DNA test eventually confirmed the little girl's parentage, and Albert extended an offer for her to live and study in Monaco.
For the moment, though, the 18-year-old – who is described by the press as "a mature, sweet and intelligent girl" is continuing further education in New York.
After graduating from JSerra High School in Orange County, California – where she was an honour student and a soloist in a school choir that performed with Barry Manilow – she took up a place at Fordham University.
As well as her father's intelligence, it seems she has also inherited his love of supporting humanitarian issues.
In November 2006, the youngster visited eight islands in Fiji on a mission to help bring the local children assistance relating to education, medicine, and community development.
In the case of both of his children, Albert is keen to shield both of them from the spotlight.
"What matters to me is that they are certain of my affection for them," he told magazine Paris Match.
He is not alone in his desire to shield his children – his sister Stephanie is equally protective of her daughter Camille Marie Kelly, whose father she has not identified.
With this in mind, it is perhaps understandable why Albert and Charlene have declined to ask any of the Grimaldi children to appear as bridesmaids, flower girls or page boys.
Instead the couple are giving their citizens the chance to be a key part of their special day.
They have selected six bridesmaids and two page boys from Monaco and the surrounding communities of Cap d’Ail, la Turbie, Menton, Beausolei and Peille Roquebrune.