"She laughed out loud for the first time with me, and it was just so cute to hear that laugh out loud," Nikki Bella tells PEOPLE her her new niece

By Jen Juneau
August 24, 2017 12:50 PM

Twin sisters Nikki and Brie Bella may have a tight-knit relationship, but there’s still room for one more little diva in there — Brie’s baby girl Birdie Joe!

The 33-year-old Total Divas and Total Bellas stars visited the PEOPLE Now studios to talk about their bond with each other and the 3-month-old newest addition to Brie and husband Daniel Bryan‘s household.

“I was nursing her, and she looked up at me and she gave me this smile — and babies can’t fake smile. They don’t fake anything, right? They let you know how they feel,” Brie recalls.

“And this genuine smile just came on, and it literally makes me want to tear up right now, but it was just like, ‘Whoa,’ ” she continues. “How I felt in that moment, I was just like, ‘This is the most incredible thing in the world.’ ”

Want all the latest pregnancy and birth announcements, plus celebrity mom blogs? Click here to get those and more in the PEOPLE Babies newsletter.

RELATED VIDEO: Brie Bella and Daniel Bryan Welcome Daughter Birdie Joe

Nikki’s favorite moment with her baby niece is the moment the latter belly laughed for the first time — and it was for her aunt!

“Birdie and I do have a super-special bond,” says Nikki who, along with her fiancé John Cena, will be shown moving in with her sister and Bryan, 36, to help Brie through her pregnancy in the upcoming second season of Total Bellas.

“She laughed out loud for the first time with me, and it was just so cute to hear that laugh out loud,” Nikki adds. “And then she giggled for the first time with me! And seeing her giggling and how happy … I was melted. Fully melted.”

“[Nikki]’ll leave the room and I’m like, ‘Birdie,’ and I’ll try to mimic [Nikki], but she won’t laugh hard at me and I’m like, ‘Ugh,’ ” Brie says. “She only laughs hard at [Nikki]!”

The sisters share that they have mom hopes for some of their fellow WWE women, after seeing how they interact with baby Birdie.

“I tell her, ‘You need to be a mom ASAP,’ ” says Brie of SmackDown star Naomi. “She babysat Birdie and she did insane, and Birdie loved her.”

“And it was cute because even Natalya, who’s one of my close friends … she’s like, ‘I never want kids, but Birdie just gave me baby fever.’ I was like, ‘Yes!’ ” Brie adds.

FROM PEN: Ali Fedotowsky-Manno Admits She Will “Definitely Support” Baby Molly If She Wants To Be The Bachelorette!

“You’ll actually get to see all that on Total Divas season 7, after Total Bellas season 2,” shares Nikki, who will also compete on season 25 of Dancing with the Stars, premiering Sept. 18. “And I was there watching them and I’m like, ‘Oh my gosh, Naomi needs to be a mom ASAP.’ ”

Another member of the maybe-moms WWE Superstars club? “Nia came to visit us at our hotel room a few days ago because she was like, ‘No, I have to see Birdie, I don’t care how busy I am,’ ” Nikki says.

Adds Brie, “She was like, ‘Brie, go do something, I got this.’ I’m like, ‘Hell yeah, this is a mom’s dream.’ ”

Total Bellas returns for season 2 on Wednesday, Sept. 6, airing at 9 p.m. on E!.