Hundreds of thousands of people took to social media to wish the mum-to-be all the luck in the world in the final stages of her pregnancy, commenting on how beautiful Kayla was.
"You're stunning! You're the most beautiful pregnant lady I've ever seen," one woman wrote.
Others claimed the celebrity personal trainer appeared to be positively glowing in her blush pink figure-hugging dress and nude heels.
"Motherhood looks good on you," one person wrote.
Another added: "You guys are just the cutest! And that baby girl has hit the genetic gene pool jackpot!"
The pair are known to go all out with celebrations, and recently revealed their baby's gender in a beautiful balloon popping ceremony which they posted to Instagram.
But as the excited mum-to-be gushed beside her fiance, others suggested the baby shower set-up was a bit over the top.
"This baby shower is so extra," one fan wrote on the fitness star's Instagram post.
Another added: "It's a bit extravagant for me lol".
Many people had questions for Kayla about how much her "intense" balloon installation had actually cost, and whether or not it could be replicated by someone with a normal budget.
"I'm sure we'll have enough money in our budget to recreate this look?" one person joked.
Another woman offered some reassurance to those who were disappointed they wouldn't be able to afford a shower similar to Kayla's.
"You can still do it this cute and nice, without being rich."
But it did little to stem the flow of comparisons from people hoping to throw a baby shower for friends and family.
"OK rich and famous baby shower dreams lol" one person wrote.
"Her life is literally so perfect," another person claimed.
The party was also slammed by one commenter who baulked at the wastage the party would have generated.
They wished Kayla good luck in her pregnancy, but wished her shower had used more environmentally-friendly party supplies.
"Good luck but all that plastic … uuuuh," they wrote.
"Littering the world is not helpful for your kid's future."
"Not to think about all the species that we chase on the brink of extinction when acting thoughtless."
Fans of Kayla and her well-known foodie sister, Leah Itsines, commented that the famous fitness family always managed to "make these parties so glamorous" and wanted to know their secret.
"How is this even humanly possible," one wrote.
They were, of course, referring to a similarly jaw dropping Pearce-Itsines event that occurred this year.
Tobi Pearce threw an opulent surprise engagement party early this month to surprise his pregnant fiance.
Dressed in white, Kayla was blindfolded and led to a mammoth marquee, decked out with thousands of fairy lights and candles, a white floral wall to rival Kim and Kanye's wedding and custom signage spelling out: "The Pearce Family".
Many couldn't believe Kayla was able to stand in a pair of stilettos at her engagement party and baby shower, at almost full-term pregnancy.
"Pregnant in heels. I can't wear them and I haven't been pregnant for 8 years!" one person said.
Another fan agreed, saying: "Legit how are you even wearing heels while preggo."
She even copped some criticism for teetering on high heels at such a late stage in her pregnancy.
"On heels? And she is a health and fitness advisor," one person wrote.
The personal trainer has kept nothing about her pregnancy quiet, posting regular photos of her bump's progression throughout the months.
But fans hadn't seen Kayla's baby bump "pop" until her baby shower, where she claimed her "muffin has turned into a basketball".
Another mother passed on a wise word of warning to the glamorous, glowing mother-to-be.
"Enjoy it now and get as much sleep as you can. It's the only thing you will be missing for the rest of your life!" she wrote.
News.com.au has contacted Kayla for comment.
