Watch out, ladies, there is an international invasion of eligible royal bachelors. TLC's new series, "Secret Princes," which premieres on Sept. 21, follows four noblemen as they leave their countries to live and work in the U.S. From left to right: Lord Robert Walters, Prince Salauddin Babi of India, Honourable Ludovic Watson of Houghton Hall and Prince Francisco Joaquin de Borbon von Hardenberg. (TLC)