Rihanna, who grew up in the island nation, witnessed the historic ceremony that broke Barbados's centuries-old ties with the British monarchy and swore in its first president Dame Sandra Mason, ending the Queen's role as head of state.
Barbados Prime Minister Mia Mottley surprised the invited guests when she said her government had recommended the celebrity be made a member of the Order of National Heroes on Wednesday.
During the ceremony applause rang out in National Heroes Square in the capital Bridgetown, when Dame Sandra was sworn in by chief justice Sir Marston Gibson and announced as "Her Excellency Dame Sandra Prunella Mason President of Barbados".
The Prince of Wales represented the UK at the televised open-air ceremony and in a speech was also warmly acknowledged by the guests when he told the new republic: "I shall always consider myself a friend of Barbados."
Charles' speech was a positive message, as if written for a close acquaintance, harbouring no regret at the decision taken by the Barbadian leaders, and it also acknowledged Britain's role in the "appalling atrocity of slavery."
He listed the ways he will "remain deeply committed to this very special country", highlighting the ongoing efforts of his Prince's Trust International charity in supporting Barbados's young people and his work with their government on issues like climate change.
Rihanna, who flew back to Barbados for the event, touched her heart as she was praised by Ms Mottley, who quoted the singer's own lyrics as she said: "May you continue to shine like a diamond and bring honour to your nation by your words, by your actions and to do credit wherever you shall go."
The culture, history and achievements of Barbados were celebrated with music, dance and spoken word during the ceremony and a number of poets and activists criticised the colonial past of the island nation and called for it to embrace the opportunities of becoming a republic.
Poet Cyndi Celeste summed up the mood when she said: "Today, after successive governments have tried and failed to rekindle the flame, we finally raised the flag of a nation no longer clinging to colonial coat tails for its identity.
"And maybe, we've been so focused on searching for the problems that we do not recognise the opportunities we have been given... shedding the vestiges of a monarchy means we get to denounce the moniker of 'little England' and vest the powers of the state in every Barbadian citizen."