In an exclusive sneak peek at Thursday's episode of Total Bellas, Nikki tells her twin sister that she's expecting her first baby with fiancé Artem Chigvintsev.
"I'm pregnant," she says as she hands Brie the positive test.
"No," Brie says, in complete disbelief. "I'm so confused."
Brie says she's especially "shocked" after Nikki confided in her that she "freaked out a bit" following her surprise engagement to Chigvintsev.
"I don't know how to feel, I'm in shock," Nikki says.
"I'm in shock!" Brie replies.
When Nikki admits that she wasn't planning to get pregnant, Brie becomes even more concerned.
"I'm very protective over my sister, and I don't want my sister to rush into everything," Brie explains in a confessional. "I feel like everything has been rushed with her lately. I don't want to take away from her having this child because it's such a beautiful thing, but when someone tells you that they feel like things have been moving too fast and less than 24 hours they tell you they are carrying that person's baby — how does one handle that?"
Pa Wire/Zuma Brie and Nikki Bella
"I just want to make sure she has a strong head on her shoulders because her whole life is about to change," she adds.
In January, Nikki and Brie revealed to PEOPLE that they are both pregnant and due only days apart.
"We kind of had a heart scare," Nikki said. "Artem and I had to drive to L.A. to get our baby double-checked because [my doctors] thought they saw something in our baby's heart."
"Everything came out great, which we were so blessed and happy about," she continued. "We are so grateful to God that the baby's very healthy."
In April, Nikki also got candid about how her body had changed throughout her pregnancy. "I don't think my feet have ever been this swollen in my entire life," she admitted on her Instagram Story. "But I can't even walk anymore! This is so sad."
In an exclusive chat with PEOPLE, Nikki revealed that as "a first-time mom," she's "really bummed" to have to forgo things like going to parenting classes with her fiancé and having a baby shower amid the coronavirus crisis. But she's looking on the bright side and counting her blessings, despite her disappointment over other aspects.
"My baby and I are healthy," she told PEOPLE. "I feel so grateful for that because of what the world is going through and the people that are dying and struggling, but obviously this is not what I imagined."
Total Bellas airs Thursdays (9 p.m. ET) on E!