Dominique Geisendorff and Cam Gigandet are expecting their third child! Credit: Barry King/FilmMagic

O.C. alum Cam Gigandet and his fiancée Dominique Geisendorff are expecting their third child together, Geisendorff shared with fans on Memorial Day, May 25.

“So thankful for the troops out there that protect this little (expanding) family of mine... #beyondgrateful #notgratefulforthegnarlymorningsickness,” the 30-year-old mom captioned her Instagram on Monday. 

Gigandet and Geisendorff are already parents to 6-year-old daughter Everleigh Rae and 2-year-old son Rekker Radley.

The Twilight star, who will next appear in Broken Vows, gushed about the arrival of his youngest child on Facebook after Geisendorff gave birth in January 2013.

“We are humbled to have the opportunity to call ourselves the parents of this beautiful soul, and I am forever grateful to God for allowing me to know this kind of boundless, immaculate love," the actor shared. "Thanks to those of you who wish to send your positive energy and well wishes."

The couple have been engaged since 2008.