When her new son, Romeo, was 12 days old, celebrity mother Hilaria Baldwin had enough energy – and confidence – to slip into lacy, black lingerie and take a mirror selfie.

Then the yoga devotée, who has had four children in four years with actor husband Alec Baldwin, 60, posted to social media the photo showing her snapped-back body.

“I just started being able to work out yesterday”, Mrs Baldwin, 34, captioned the photo, posted with a side-by-side shot taken when she was nine months pregnant with 3.6-kilogram Romeo.

“Slow and steady, nothing crazy. Every body is different, but I believe in staying as active as possible”.

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A post shared by Hilaria Thomas Baldwin (@hilariabaldwin)

Her approach may not have been crazy, but the reaction was.

The photo created online blowback for Hilaria, who has had four children in as many years: Carmen, 4, Rafael, 3 next month, Leonardo, 20 months, and now Romeo, born on May 17.

Some followers found the image empowering, with others devastated by it: “I need to turn in my I’m-a-woman-card”, wrote one on Instagram.

“Well, this doesn’t uplift me. It makes me feel … bad, less than,” wrote one of her followers.

“Maybe instead of pictures of how great you look, you could focus more on the exercises for those of us who are more genetically challenged”.

Said another: “I don’t know how I feel about this, but I do know that this is the first time I had to stop myself from saying something snarky and hurtful to you.

“You’re gorgeous, but unbelievable post-Romeo pic makes everyone else feel angry they can’t achieve your success. Sad but true.”

Said another: “This seems like posting to fish for compliments under the guise of ‘helping people see a normal body’.”

For all the critics, Mrs Baldwin had plenty of admirers, too.

“Super”, said one. “You look great”, noted another, while a third got practical: “How did you prevent stretch marks?”

It’s not the first time Mrs Baldwin has used social media to make what she has called a statement about body expectations after having a baby.

The day after having Romeo, she drew criticism for sharing a similar mirror selfie.

“Given the right love and care, we can feel really good within our skin,” posted Mrs Baldwin. Photo: Instagram

She did the same thing with her two older sons, but with Carmen, “I was too much of a nervous mama”, she wrote.

“My purpose is to normalize the postpartum figure”.

Mrs Baldwin even admitted her magic slimdown wasn’t as easy as she’s made it look: “There were so many moments when I didn’t want to work out this pregnancy. Showing up is the most difficult challenge,” she tweeted.

“I had to drag myself out and do even a little. Consistency helped me so much though”.

Despite apparently having everything under control, Mrs Baldwin has had a lot on her plate since welcoming Romeo on May 17. Eight days after giving birth, she was diagnosed with pneumonia, then Leonardo and Rafael went down with flu and Carmen developed conjunctivitis.

The Baldwins all managed to get out of their New York home on May 29 for a stroll around the city, with Hilaria carrying Romeo in a baby pouch while pushing Leonardo’s stroller.

Still, “it’s been tough getting our new family of 6 oriented with all of the necessary quarantining”, Mrs Baldwin wrote on Instagram.

“The recovery from birth, the beginnings of breastfeeding again, the sleepless nights, taking care of sick toddlers, dr visits, my own health … I just keep on saying ‘we got this’”.

Alec and Hilaria Baldwin with Carmel and Rafael at a New York premiere in March 2017. Photo: Getty

For Canberra event manager and mother-of-three Ashleigh Gleeson, the controversial photo sparked a mixed reaction.

“Well, I mean it’s amazing her body snaps back like that. Mine did not,” Mrs Gleeson, who has children Rylan, 4, Finley, 3, and Darcy, 1, with husband Jo Gleeson, told The New Daily.

“If it was me with a 12-day-old I would have the giant pants on, the kind that hold your belly together, and be wearing my husband’s tracksuit pants.

“I would definitely not be brave enough to do what she did, but I don’t begrudge her for it. It’s not a jealous thing, it’s more admiration and curiosity about how she did it.”