EXCLUSIVE: Daniela Ruah and Sarah Wright Olsen Dish on Real-Life 'NCIS: Los Angeles' Baby Triangle

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NCIS: Los Angeles stars Daniela Ruah and Eric Christian Olsen play lovers on the CBS series, but in real life, they're in-laws!

Daniela is married to Eric's older brother, David, while Eric is married to actress Sarah Wright, and coincidentally, both couples are already parents to little boys and they each have girls on the way.

PICS: 'NCIS: Los Angeles' Star Daniela Ruah Is Pregnant With Baby No. 2!

"I've just always wanted one of each," Daniela told ET. "I have a really great relationship with my mom, and she said to me, 'I would have been happy no matter what you had, but as a mom, I'm happy that you get to have the experience of having a girl.'"

The two sisters-in-law dished to ET on the experience of going through their pregnancies simultaneously, and Sarah said her husband is carrying a lot of weight on his shoulders.

"I think the person who has the most challenge from all of this is Eric, because he goes to work and he has to be with her and he comes home and he's with me," she joked with ET.

Making things even more intertwined, David is Eric's stunt double on NCIS: Los Angeles. But one upside to working with so many family members is the support Daniela has gotten on set.

WATCH: 'NCIS: LA' Stars Eric Christian Olsen and Daniela Ruah on Densi

"It really is difficult to plan around something like this," she said about breaking the pregnancy news to the cast and crew. "They all sort of smiled on their faces like, 'We have this. Don't worry about it.' ... It's a very family-oriented show and everybody has kids."

The ladies' due dates are within weeks of each other and they're also both going through pregnancy cravings.

"I was walking by this aisle and it was just Flaming Hot Cheetos," Sarah said. "I was like, 'I want those!'"

"I'll totally indulge in chocolate," Daniela chimed in.