The Las Vegas actress revealed that she and her husband Scott Stuber are expecting their first child together after conceiving during their honeymoon.
The 38-year-old, who married Stuber in September, said that the pair are "thrilled" to become parents in June.
"I am absolutely, positively, downright over the moon to announce that we are pregnant! There are simply no words to describe the feeling," she wrote on her official website.
"I finally get what they mean when they say pregnant women glow. Our little bundle of joy is a honeymoon baby, due at the end of June. A first pregnancy is a nerve-wracking experience of course, but mostly we are just thrilled and excited. We can't wait to meet him or her."
Sims added that she found a unique way of telling her husband that she was pregnant, saying: "I hijacked the fortune cookie and typed a new message so that when he opened his cookie at the end of the meal, he found out he was going to be a daddy.
"You can only imagine how nervous I was during the entire meal (I think I ate a total of two bites.), but the look of surprise and pure joy on his face was priceless."
Sims recently signed up for a guest appearance in Royal Pains.