William is the eldest son of Charles and his first wife, Princess Diana, and second in line to take the throne. William currently serves as a helicopter pilot in the Royal Air Forces’s Search and Rescue Force. After marrying longtime girlfriend Kate Middleton, now Duchess of Cambridge, in 2011, the couple announced in December 2012 that they were expecting their first child. William is known as Earl of Strathearn and Baron Carrickfergus.

Alastair Grant/AP/File
Britain's Prince William stand next to his wife Kate, Duchess of Cambridge, as she leaves the King Edward VII hospital in central London, Dec. 6, 2012.