Katharine McPhee's family is coming to her defense.

The 37-year-old "American Idol" alum made headlines earlier this week when her husband, music legend David Foster, shared a photo of her in a bikini on Instagram.

"What baby!" he captioned the pic of the trim star, referencing the birth of their son Rennie 10 months ago.

Some followers were unhappy with the 72-year-old songwriter's post, calling it "cringe worthy" for encouraging women to "bounce back" to their slim figures after giving birth.

KATHARINE MCPHEE HITS BACK AT 'OVERLY SENSITIVE SOCIETY' FOLLOWING CRITICISM OVER BIKINI PHOTO: 'GET A LIFE'

Katharine McPhee's husband David Foster faced criticism for praising the singer's body 10 months after she gave birth.

Katharine McPhee's husband David Foster faced criticism for praising the singer's body 10 months after she gave birth. (Getty Images)

On Wednesday, McPhee shot back in her own Instagram post, discussing her struggles with her weight for nearly two decades.

"I lost this baby weight without dieting. Zero. Diets are the worst and I’ve had zero pressure from anyone," she shared. "I’ve let me body do its thing and found a great workout. That’s it. And guess what? I’ll probably gain weight again at some point too. Who cares?"

DAVID FOSTER GUSHES OVER KATHARINE MCPHEE AS SHE POSES IN BIKINI 10 MONTHS AFTER WELCOMING SON: ‘WHAT BABY’

She also suggested that followers "stop being so offended by what people post who have zero impact on your life and move on."

Foster's daughters Sara and Erin shared their thoughts on the matter on Instagram, praising their stepmother for having pride in her body.

Foster's daughters Sara and Erin shared their thoughts on the matter on Instagram, praising their stepmother for having pride in her body. (Getty Images)

Her stepdaughters – reality stars Erin and Sara Foster – then stepped in to echo the singer's sentiments.

SARA, ERIN FOSTER FELT ‘EMOTIONAL TURMOIL’ WHILE DAD DAVID FOSTER RAISED JENNER BOYS

"If I can accept my step mom looking like this, you certainly should be able to," Erin, 39, commented. "The photo wasn’t altered or filtered and she’s had no surgery. You can’t shame someone for feeling cute after a baby whether she’s sharing stretch marks or a six pack. Let her live."

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McPhee hit back at critics in her own Instagram post.

McPhee hit back at critics in her own Instagram post. (Getty Images)

Added Sara, 40: "If you [would have] had cellulite and stretch marks in the photo and the caption was exactly the same we would all be celebrating his post. But you don't and that's not allowed to be celebrated."

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Furthermore, Sara pointed out that the "Country Comfort" star has been "working your a-- off at the gym."

"Let's complain about women and husbands who post 3 week postpartum pics with their full body lipo, filters and altering apps that make us all feel like s--t," she continued. "People are crazy."