Donald Trump is hosting a dinner at the US ambassador's residence.
Charles and Camilla were among the guests attending the event at the house in Regent's Park, where the US President and First Lady Melania Trump are staying during their state visit.
Thousands of protesters lined the streets throughout the day to protest against Mr Trump's visit.
Labour leader Jeremy Corbyn was among those who spoke out against the US president, condemning Mr Trump for his attacks on mayor of London Sadiq Khan.
It all came as Mr Trump promised a "phenomenal" trade deal with the UK post-Brexit as he held a joint press conference with outgoing Prime Minister Theresa May.
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