'MILF!' Size 22 model Tess Holliday proudly shows off her post-baby body in a bikini just three weeks after giving birth to son Bowie

Tess Holliday is already back in a bikini and enjoying some fun in the sun just three weeks after the birth of her son Bowie Juniper. 

The 31-year-old mother-of-two took to Instagram on Monday to share photos of herself donning a two-piece while celebrating the Fourth of July at a rooftop pool in Los Angeles.

During her relaxing holiday, the size 22 model posted the playful snapshots along with a brief message about body positivity, simply captioning one image of herself holding an inflatable doughnut with the hashtags '#MILF, #4thofjuly, and #effyourbeautystandards'.

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Poolside: Tess Holliday took to Instagram on Monday to show off her post-baby body in a two-piece swimsuit during her Fourth of July celebration 

Lounging: The 31-year-old mom, who gave birth to her son Bowie Juniper on June 13, also posted a photo of herself posing on top of a flamingo raft 

In the photo, which was taken just one day before her 31st birthday, Tess can be seen giving the peace sign with one hand while holding the pool toy in another. 

The social media star's auburn hair is pulled back in two French braids as she proudly shows off her post-baby body in a black and hot pink bikini top, which she paired with high-waisted bottoms. 

Another picture sees the mom sitting on top of an inflatable flamingo with her legs wrapped around the neck of the pool float. 

In addition to a pair of round, oversize sunglasses, Tess also donned gold star earrings that are shaped like a sheriff's badge.  

Although Bowie wasn't featured in any of the poolside pictures, Tess was joined by the little boy's father — her fiance Nick Holliday. 

Fun couple: Tess was joined by her fiance — and Bowie's father —Nick Holliday as they enjoyed the holiday 

Showing off: Tess donned a similar swimsuit when she visited the rooftop pool on Memorial Day weekend when she was nine months pregnant with Bowie 

Nick took to his Instagram account on Monday to share a heartwarming photo of him and Tess floating on the raft together, writing: 'Pink flamingos.'

Tess is laughing in the playful snapshot, which sees her sitting in between Nick's open legs on the inflatable toy.

The model also has a ten-year-old son, Rylee, whom she had with a previous boyfriend she no longer speaks to, and just a few days before her Fourth of July celebration, she shared a Snapchat video of her and her eldest son using the app's dog filter. 

'My oldest pup. His smile is infectious,' she captioned the clip, which sees them happily sticking out their tongues. 

Tess frequently shares candid photos of her family on social media, and last week, she posted an intimate photo of herself nursing her newborn son. 

Fun times: A few days ago, Tess shared a Snapchat video of her and her 10-year-old son Rylee using the app's dog filter 

A mother's love: The mother-of-two posted this photo of Bowie nursing to celebrate being able to breastfeed while lying down for the first time 

Sleepy baby: Tess has been actively sharing photos of Bowie since welcoming him into the world  

'I had to capture this moment because today was the first time I was successful at feeding lil Bowie laying down #normalizebreastfeeding #motherhoodrising,' she captioned the black and white image, which sees her holding her son's head while he suckles her breast during his feeding.

The photo was taken by Nick, who couldn't help but gush about his fiancee when sharing the snapshot on his Instagram page.   

'A lot of people seemed to get upset that @tessholliday posted a photo hashtagged "#normalizebreastfeeding" which didn't actually feature the act of breastfeeding,' he wrote. 'So here you go. She actually looks really sexy here — but it isn't always like that.

'Sometimes it's stressful and messy and nothing goes how you want it to. But sometimes it's bliss. Don't let anyone make you feel bad about feeding your child, wherever that may be, and for the women out there who can't breastfeed, don't let anyone make you feel bad about that either.'

He later returned to the post to add: 'Finding a plus size mother (two groups robbed of all sexuality) with whom I am in a relationship "sexy" for being a good mum is not the same as objectifying strangers body parts in public.' 

Speaking out: The mom is also an advocate for normalizing breastfeeding 

Doting dad: On Father's day Nick shared photos of himself with his future stepson Rylee (left) and his newborn Bowie (right)

Tess and Nick welcomed their son on June 13, and at the time of his birth, Bowie weighed 8lbs, 10oz and measured 22 inches long.

The baby's name is presumably inspired by the late musician David Bowie, whom Tess publicly mourned on social media after his death in January. 

A week after they announced the birth of their son on Instagram, Tess posted a precious photo of Bowie curled on her chest.   

'Mondays are a dread by all, sometimes even the self employed like myself,' she captioned the image. 'Now I find that the days blur together of breastfeeding, sleeping when I can, tears of happiness (& sometimes fear), & no longer having a case of "The Mondays".

'Because every day is a new adventure when you see it through your little ones eyes #motherhoodrising #normalizebreastfeeding.'

Throughout her pregnancy Tess became an even more vocal body advocate, sharing plenty of candid photos of her growing baby bump as well as nude photos to celebrate her changing body.