Queen Elizabeth has welcomed the emir of Kuwait, Sheik Sabah al-Ahmad al-Jaber al-Sabah, to Windsor Castle for a three-day visit.
It was the first time the red carpet was rolled out for a state visit by an emir from the oil-rich state in 17 years.
Sabah, 83, will have a private audience with the Prince of Wales and meet British industry leaders. He will also meet Prime Minister David Cameron.
The Duke of Edinburgh escorted Sabah to inspect the guard of honour at the castle.
Sabah became emir in 2006, although he had been running Kuwait's day-to-day affairs for years. He became prime minister in 2003.
Kuwait is the third largest trading partner of the UK in the Gulf region, with the volume of trade exchange between the two reaching $3.59bn.
There are about 50 British companies working in Kuwait, in construction, oil, defence, real estate, logistics and banking sectors.