The Prince of Wales and Duchess of Cornwall have been hobnobbing with some of America 's biggest stars during a reception in London this evening . Charles and Camilla were at an event for Americans living and working in the UK ahead of their visit to the USA . They mingled with designer Tom Ford , Downton Abbey star Elizabeth McGovern , and Hunger Games and Fortitude actor Stanley Tucci . Scroll down for video . Prince Charles meets Elizabeth McGovern , right , who plays Cora Crawley , Countess of Grantham in the ITV series Downton Abbey . They were at a reception for Americans living and working in the UK at Winfield House in London . Camilla wore a blue lace cocktail dress by Edina Ronay to the reception which was hosted by US Ambassador Matthew Barzun and Brooke Brown Barzun at Winfield House in the capital . The royal couple will make a four day visit to the US on March 17 , spending much of their time in Kentucky and Washington D.C . They will undertake a range of engagements to promote the UK 's partnership with the US in areas such as sustainability and climate change , creating youth opportunities , encouraging corporate social responsibility . The couple will also be in the country to promote historical and cultural links between the two nations and will have a meeting with President Obama at the White House . Camilla , Duchess of Cornwall , meets fashion designer Tom Ford , centre , and his husband , writer and journalist , Richard Buckley , left . Charles and Camilla meet Elizabeth McGovern , right , and actor Stanley Tucci , second right , flanked by U.S . Ambassador to Britain Matthew Barzun , fourth left , and his wife Brooke Barzun , second left , . Charles has visited the US in an official capacity 19 times since 1970 , and his last visit was in May 2011 when his programme included a call on President Obama at the White House . Camilla has visited the US officially twice with Charles - in 2005 and 2007 . Their visit in 2005 was their first official overseas tour conducted jointly as the Prince of Wales and the Duchess of Cornwall and came just months after their wedding . Earlier , the royal couple had spent the afternoon at Westminster Abbey alongside the Duke and Duchess of Cambridge , the Queen and Prince Philip . The sextet were there to mark Commonwealth Day , an organisation of 53 nations of which the Queen remains head . Both the Queen and the Duke of Edinburgh and Prince Charles and the Duchess of Cornwall will travel to Maltese capital Valletta in November for the bi-annual Commonwealth Heads of Government meeting . Charles meets American-British playwright , novelist and critic Bonnie Greer . Charles and Camilla pose for a group photograph with U.S . Ambassador to Britain Matthew Barzun , third left , and his wife Brooke Barzun , right .
Duke and Duchess of Cornwall attended event celebrating Americans in UK . The couple were seen smiling as they posed for photographs with the Queen at a reception held by Prince William and his wife Catherine, who are on their first official visit to Britain.