Hats! Jewels! Dresses! Tiaras! State visits are as much about what everyone is wearing as they are about what they’re saying and doing.

Axar.az reports, citing BBC, it is an exercise in fashion diplomacy - and there has been plenty of it on display as US President Donald Trump and his wife Melania visit the UK.

From the First Lady's hat and striking yellow banquet dress, to the Princess of Wales's golden gown and historic tiara, here are some of the most eye-catching looks.

At Wednesday night's formal state banquet, Melania went bold.

Yellow. And a baby pink belt.

The strapless floor length, long-sleeved dress by Carolina Herrera is nothing short of a statement.

Gone was the hat, so for the first time on Wednesday, we saw her full face. She wore her hair down, and completed the look with sparkling, dangly earrings.

The Queen, 78, attended the evening banquet wearing a royal blue, silk, marocain embroidered dress by Fiona Clare, a sapphire and diamond tiara, and the King's Family Order.

Notably, some people interpreted this as a symbol of joint support by the U.S. and the U.K. for Ukraine.

King Charles's regalia was in keeping with the high pomp and pageantry that we would expect of a state banquet.

He wore a formal tuxedo, looking "every inch the monarch", noted Kwei.

The King, 76, completed his look with a royal blue sash - a colour that matched Camilla's dress.

Meanwhile President Trump, 79, dressed the part for the evening's event in white tie.