President Bush is welcoming Britain's Queen Elizabeth and her husband Prince Philip to the White House at this hour.
Seven-thousand guests, including diplomats, lawmakers and other notables, are attending the arrival ceremony on the South Lawn of the White House.
Tonight, Mr. and Mrs. Bush will host a state dinner for the royal couple. Attire for the men this evening will be white tie, the first such extremely formal event of Mr. Bush's presidency.
On Tuesday, the Queen will tour the Children's National Medical Center in Washington and the nearby NASA Goddard Space Flight Center. She will also lay a wreath at the National World War Two Memorial before heading back to London.