Ashlee Simpson Says Sister Jessica's Newest Arrival Birdie Mae Has Given Her Baby Fever

Ashlee Simpson Ross has babies on the brain!

Three days after big sis Jessica Simpson welcomed her third child, Birdie Mae Johnson, Ashlee, 34, appeared on the Daily Pop with husband Evan Ross, where she revealed that meeting her new niece made her want more kids.

Ashlee is currently a mom of two — she shares daughter Jagger Snow, 3, with Evan, and son Bronx Mowgli, 10, with ex-husband Pete Wentz.

“I’m not pregnant but it definitely gave me the [baby] fever a little bit,” Ashlee joked to the show’s hosts.

The “Pieces of Me” singer also noted during the interview that the newborn, mother, and family were doing well after Birdie’s delivery this week.

“Oh my gosh, she is so cute,” she said of her new niece. “[Everyone is] amazing, so great. The kids were so cute — Jessica’s kids with their little baby sister.”

Jessica, 38, and her husband Eric Johnson welcomed daughter Birdie Mae on Tuesday, March 19, her rep confirmed to PEOPLE exclusively.

Baby Birdie weighed 10 lbs., 13 oz.

RELATED: She’s Here! Jessica Simpson and Husband Eric Johnson Welcome Daughter Birdie Mae

“We are so happy and proud to announce the birth of our perfect daughter, Birdie Mae Johnson,” Jessica wrote on Instagram Wednesday, sharing a black-and-white photo of her older daughter meeting the new addition.

Ashlee also shared the same photo, writing on Instagram, “My heart is so full!! Welcome to the world Birdie! ❤️”

Jessica and the former NFL player also share son Ace Knute, 5, and daughter Maxwell “Maxi” Drew, 6½.

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Though Birdie is only a few days old, she is sure to fit in with her siblings and cousins, as Ashlee and Jessica’s kids have previously proven to be a tight bunch.

The sisters brought their respective broods together for some quality family time in February 2016, and the photographic evidence couldn’t be more adorable.

RELATED: All in the Family: Jessica and Ashlee Simpson’s Kids Are Already Besties

In one image, Jessica’s son Ace snuggled up to Ashlee’s daughter Jagger. The trendy tot plopped a sweet kiss on Jagger’s head, which Jessica captioned, “Ace and Jagger #COUSINS.”

The families celebrated New Year’s Eve together in 2016, where they snapped a photo. “Such a fun New Years. Happy 2016! Great family vibes!!” Ashlee wrote.

RELATED: Jessica Simpson Says She’s ‘Shocked’ Sister Ashlee Wanted to Return to Reality TV

And last May, the sisters had a girl’s day at Disneyland with their daughters. In one shot, shared on Jessica’s Instagram, the group smiled as they posed with Minnie Mouse.

“So “Minnie” great memories #Disneyland,” Jessica captioned the shot.

Most recently, Ashlee was by her sister’s side during Jessica’s “Birdie’s Nest” baby shower in January.

At the celebratory event, Jessica revealed her baby girl’s name and completed the party with a neon sign and whimsical table settings encouraging guests to “stuff your beaks.”

RELATED: Jessica Simpson Celebrates Daughter on the Way at Stunning ‘Birdie’s Nest’ Baby Shower

“It was a great day. Jessica is feeling very loved,” a source revealed to PEOPLE at the time. “She felt very loved, surrounded by her closest friends and her mom and her sister.”