King Charles is hosting the first Nigerian state visit to the UK for 37 years, with President Bola Ahmed Tinubu and his wife Oluremi Tinubu receiving a ceremonial welcome at Windsor Castle.
At the start of the two-day visit, the leaders of the African nation with the biggest population - triple that of the UK - were greeted by senior royals including Queen Camilla, and the Prince and Princess of Wales.
The King and President Tinubu will give speeches on Wednesday evening at the state banquet, which will be attended by political leaders and celebrities with links to Nigeria.
However, there will be no traditional lunch with the King at Windsor as the president is a Muslim and fasting for Ramadan.
In warm spring sunshine, the president and first lady - wearing traditional robes - were given the ceremonial grandeur of a royal welcome, including a carriage procession and military band.
President Tinubu and Mrs Tinubu had been met earlier by Prince William and Catherine, Princess of Wales, before being escorted to formally meet the King and Queen.
Official gifts were exchanged. The president and Mrs Tinubu were given hand-crafted pottery, a silver photo frame containing a picture of the King and Queen and a silver and enamel bowl, while the King and Queen received a traditional Yoruba statuette and a jewellery box featuring the faces of important Nigerian women.
The visit also aims to strengthen business links, including financial services, with Nigeria's Zenith Bank recently opening a branch in Manchester.
Later, President Tinubu and his Christian wife will lay a wreath at the tomb of the late Queen Elizabeth II, followed by speeches in the evening at the state banquet.
On Thursday, Mrs Tinubu, an ordained pastor, will preach at a service at Lambeth Palace and meet representatives from the Church of England.
