"May you continue to shine like a diamond and bring honour to your nation by your works, by your actions," PM Mottley told the singer.
In 2018, the government of Barbados gave the singer, whose Robyn Rihanna Fenty, an ambassadorial role. The role meant she would promote education, tourism and investment in her home country.
PM Mottley said Rihanna, one of the best-selling singers of all time, "has a deep love for this country".