US President Barack Obama sent his congratulations to Britain's Prince William and his wife Catherine on Monday, on news they were expecting a baby and a future heir to the throne. "On behalf of everyone here in the White House, beginning with the president and the first lady, we extend our congratulations to the Duke and Duchess of Cambridge on the welcome news this morning out of London that they are expecting their first child," White House spokesman Jay Carney said.

The Obamas met the royal couple, who were then newly weds, during a state visit to Britain last year.

"I know they both feel that having a child is one of the most wonderful parts of their lives, so I'm sure that will be the same for the Duke and Duchess of Cambridge," Carney said.