The aristocratic grandson of screen legend-turned-princess Grace Kelly is set to become a first-time father.

Andrea Casiraghi, who is the son of Kelly's daughter, Caroline, Princess of Hanover, and second-in-line to the Monegasque throne, is preparing to welcome a child with Colombian heiress Tatiana Santo Domingo.

Domingo tells Spanish newspaper La Voz Libre, "I am expecting a child. Yes, I am pregnant."

The couple became engaged in July (12) and is reportedly planning to wed in 2013.