And a baby makes four!
The TV stars announced the exciting family news, which comes just two years after Tarek was diagnosed with thyroid cancer, on Instagram with an adorable Easter-themed post.
The El Moussas also revealed that they are expecting a baby boy and that the new addition comes after a lengthy fertility battle.
"We found out Tarek had cancer, and we asked the doctor if that would affect our chances of having a child," the pregnant reality star told People magazine.
"They said that if you go through radiation, which Tarek had too, then you should not get pregnant from that sperm from six months to a year. So, right away, we did sperm banking and [tried] IVF."
After two attempts at IVF, including a miscarriage when Christina was eight weeks pregnant, the couple tried one last time to have another child.
"I had to be super strict. I had to do one full week in bed. For 13 weeks after that, I could go for a walk and couldn't lift anything over a gallon of milk," she explained.
"We planned it during Christmas break so I wasn't working. We did everything we could to make sure this one worked."
The couple broke the pregnancy news to their daughter, Taylor, who is already looking forward to being an older sister.
"She really wanted a sibling. So we kept telling her, 'Mom is really trying to make a baby.'"
Christina also dished that she "can work out now" and favors yoga, walking and Pure Barre to stay in shape throughout her pregnancy.
"I'm trying not to gain too much," she added. "I've only gained 10 pounds."
And Tarek is already looking forward to focusing on his expanding family, admitting, "It's exciting to have a son and a daughter. The second he gets old enough, I'm going to step back from work and focus on raising them."
Season 3 of Flip or Flop premieres Tuesday at 9 p.m. ET on HGTV.