Prince Albert of Monaco's love child Alexandre Grimaldi-Coste, 18, was seen out and about enjoying life in Rome with his mother Nicole, 50, the former partner of Albert.
The mother and son also attended the prestigious Rose Ball in Monaco recently.
His parents met in the 1990s at the 2000 Mare Nostrum swimming competition in Monte Carlo. Around the same time, Albert met his wife Charlene.
Alexandre isn't the only child Albert has fathered before he got together with Princess Charlene - the couple share two children - as he also had a daughter Jazmin with American Tamara Rotolo in 1992.
Charlene, 44, has recently spent periods away from Monaco life due to "state of profound general fatigue".
So who is Alexandre, said to "get along very well" with his father?
Who is Alexandre Grimaldi-Coste?
Alexandre Grimaldi-Coste is the love child of Prince Albert of Monaco and flight attendant Nicole Coste.
They had reportedly been in a five-year relationship until their son's birth in 2003. Alexandre - who has recently been signed as a model - was born in August of that year.
It wasn't until 2005 that Alexandre became public knowledge, when Nicole gave a tell-all interview to French magazine Paris Match. This was confirmed by Albert, two months before he was enthroned in Monaco.
Nicole has said: "Albert made a commitment from the start to be present, and to gradually bring his son into his family."
Albert later said he was furious about the interview with Point du Vue: "She had just informed me that she was going to release something, I thought it would be just a birthday photo. It was inappropriate, I was furious to find that out."
Who is Prince Albert?
Albert II, the Prince of Monaco, is part of the Grimaldi family who has ruled Monaco for eight centuries.
Before becoming the principality's sovereign prince in 2005, Albert, 64, was a bobsledder and competed at the Winter Olympics. He is the son of King Rainer III and Grace Kelly.
Nicole said that Albert and wife Charlene began dating two years after Alexandre was born and hinted there have been tensions between her and Albert's partner.
She said: "As for Charlene, this is a subject that I cannot avoid because we are often put in parallel. I don't like being compared. I never advertised myself as an enemy. I am a gentle woman.
"Given our respective ties to the prince, we should have made sure to support each other cordially. In our situation, diplomacy had to prevail. But during the engagement period, I experienced things that alerted and shocked me."
Albert and Charlene married in 2011, with the former Olympic swimmer from South Africa pictured in tears on the day.
He has said of his relationship with Charlene and her recent problems: "I'm probably going to say this several times, but this has nothing to do with our relationship. I want to make that very clear.
"These are not problems within our relationship; not with the relationship between a husband and wife. It's of a different nature."
