Rachel Reilly and Brendon Villegas share 4-year-old daughter Adora Borealis
Big Brother

Move over Big Brother: Rachel Reilly and Brendon Villegas' daughter is going to be a Big Sister!

The reality television alums are expecting their second child together, the couple reveal exclusively to PEOPLE.

Reilly, 35, and Villegas, 39, welcomed their now- 4-year-old daughter Adora Borealis in April 2016 and have been "trying for a while now" for a second child, Reilly tells PEOPLE.

"It was actually kind of funny because in February I got the opportunity to work with Ava Women and try out their bracelet and app. I had just started to track my ovulation cycle with the app and got pregnant on our first try!" she shares.

"We are beyond excited," she says of adding another little one to the family.

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The soon to be second-time-parents have yet to find out the sex of their baby on the way and are currently staying focused on maintaining a healthy pregnancy amid the coronavirus pandemic.

"In the midst of a pandemic, I am most concerned with Rachel and the baby both maintaining their health throughout the pregnancy. Honestly, that is all I care for at the moment, their safety," Villegas tells PEOPLE.

Reilly reveals that she's been having a "really hard first trimester," already dealing with sicknesses like shingles and a thyroid goiter, and has been struggling to eat.

"With Adora, I was really sick and emotional, with this baby I've been really sick. I've been trying to figure out what we're having by the 'old wives tales' but nothing makes sense," she explains.

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While the couple don't have their hopes set on either sex, Reilly admits it would be "fun for Adora to have a sister so she can compete on Amazing Race with her sis like I did."

"And yes I'm already planning their reality TV appearances," she jokes with a laugh.

Adora couldn't be more excited to be a big sister as she's "been asking for a baby," the couple share.

"I think she was more excited than we were. I made baby muffins and got a balloon and was like guess what?! You're finally going to be a big sister! She screamed!" Reilly recalls.

Adora has also been helping her mom to stay happy and healthy throughout her pregnancy.

"When I have morning sickness, she comes in the bathroom and rubs my back," Reilly says. "She brings me water to drink all day and she even goes and grabs water bottles and tells me I have to drink them for the baby."

The couple's daughter is already looking forward to teaching the baby new skills, like how to swim or play soccer. She'll even change the diapers, Reilly says with a laugh, "but not the stinky ones."

"She has made this even more exciting," Reilly says of her daughter.

The couple first met in 2010 on season 12 of Big Brother, before returning to the house for a second time the following year, when Reilly won. They later appeared as a couple on two seasons of The Amazing Race.

Villegas and Reilly tied the knot in September 2012 atop the AT&T Center in downtown Los Angeles.