Prince Albert paid his first visit to Ireland as a three-year-old in 1961 for a week-long holiday with his parents, Prince Rainier III and the Irish-American actress Grace Kelly; an event that whipped up such a frenzy that crowds gathered outside the Gresham Hotel in Dublin in their tousands and bunting was displayed on the streets of Cong in County Mayo.
And this week the Monaco royal returned for a third time - the second visit took place in 2011 - as he paid an informal visit to Bru na Boinne and Newgrange on Wednesday, alongside his South African wife Princess Charlene.
It was a low-key affair compared to his very first visit to this country. After enjoying a morning of sightseeing, the royal couple and their friends stopped off at The Monasterboice Inn for a spot of lunch.
"We had no idea that they were coming. We got a phone call in advance to ask us to keep a seat for 12 celebrity guests, as well as a table for six for their entourage. We prepared the tables as we would for any other visitor but we weren't too excited because we really had no idea who or what to expect."
Prince Albert may be one of the wealthiest men in the world but Ms Donegan said that the monarch behaved like a regular visitor and her staff members wwere charmed by the down-to-earth manner of the entire party.
"They were such a lovely family. They were just so down-to-earth. It was just like serving any other family in the restaurant.
"Prince Albert requested to sit in the bar but unfortunately we didn't have seats available so they sat in the restaurant. He ordered a seafood chowder and a pint of Hophouse 13."
The couple were not accompanied by their children, two-year-old twins Princess Gabrielle and Prince Jacques. They were joined by Princess Charlene's brother, his wife and their toddler son, as well as some close friends.
Ms Donegan said that their fellow customers didn't make a fuss over the royal family and they enjoyed their meal without any intrusion.
"They were wonderful guests. Princess Charlene is stunning, a really attractive woman. She was just delightful. They all were. They'd such an interest in the area. He [Prince Albert) knew all about Monasterboice. I gave them a gift when they were leaving, two books on local history from Professor Haberson. They seemed really happy with it."
During the prince's first visit to Ireland, his mother Grace Kelly visited hospitals, the Sacred Heart Home for Orphans on the Drumcondra Road and an outing for disabled children, while the prince visited a housing scheme in Coolock.
At the time, the Irish Independent reported that a crowd of around 5,000 rushed the police cordons outside the Gresham Hotel as the royal's car pulled up ahead of a banquet that was being held in their honour. Men, women and children were crushed in the ensuing melee and others fainted, while there was a report that one woman even had a heart attack.