Jessica Simpson shares a cute snap of her baby girl, one, cuddling with sister Ashlee’s newborn

Jessica Simpson shares a cute snap of her baby girl Birdie Mae, one, cuddling with sister Ashlee’s newborn son Ziggy Blu Ross

Jessica Simpson and her younger sister Ashlee Ross-Naess’ youngest kids already appear to be becoming the very best of friends. 

In the 40-year-old Open Book author’s latest Instagram post, she shared an adorable moment between her one-year-old Birdie Mae and Ashlee’s infant son Ziggy Blu, who was born in late October. 

As the cousins lounged together on one of their first playdates of 2020, Jessica’s mini-me held onto a toy elephant and wore a striped onesie. 

Mini-me: Jessica Simpson and her younger sister Ashlee Ross-Naess’ youngest kids already appear to be becoming the very best of friends

Cousins: In the 40-year-old Open Book author's latest Instagram post, she shared an adorable moment between her one-year-old Birdie Mae and her sibling's newborn son Ziggy Blu, who was born in late October

Cousins: In the 40-year-old Open Book author’s latest Instagram post, she shared an adorable moment between her one-year-old Birdie Mae and her sibling’s newborn son Ziggy Blu, who was born in late October

Meanwhile, Ziggy rested on Birdie’s arm and looked very comfortable in a fuzzy fleece snapsuit and his eyes fixated on something off in the distance. 

Ashlee, 36, welcomed her third bundle of joy just a year and a half after Jessica gave birth to her own third-born child with husband Eric Johnson on March 19, 2019. 

The close-knit sisters regularly appear on each other’s social media and support each other’s major milestones.  

Three kids each: Ashlee, 36, welcomed her third bundle of joy just a year and a half after Jessica gave birth to her own third-born child with husband Eric Johnson on March 19, 2019

Three kids each: Ashlee, 36, welcomed her third bundle of joy just a year and a half after Jessica gave birth to her own third-born child with husband Eric Johnson on March 19, 2019

A month before little Ziggy’s birth, Jessica and her eldest Maxwell Drew attended Ashlee’s baby shower and posed for a snap with the singer and husband Evan Ross’ daughter Jagger. 

In addition to her two kids with the actor, Ashlee shares her eldest son  Bronx, 12, with Pete Wentz. 

Earlier this month, the stunning sisters posed for a rare selfie with their mother Tina Ann Drew, 61.  

Family time: A month before little Ziggy's birth, Jessica and her eldest Maxwell Drew attended Ashlee's baby shower and posed for a snap with the singer and husband Evan Ross' daughter Jagger

Family time: A month before little Ziggy’s birth, Jessica and her eldest Maxwell Drew attended Ashlee’s baby shower and posed for a snap with the singer and husband Evan Ross’ daughter Jagger

The girls were wishing their mother a happy birthday. 

‘Happy Birthday to the one and only @tinasimpsonofficial! ❤️✨ The best mom, Gigi, friend and a guiding light for Team JS! We love you so much!’ said the caption from the Jessica Simpson Style Instagram page. 

On her own account, she also penned a heartfelt note praising her mother for being ‘the most deserving person of happy.’ 

A rare snap: Earlier this month, the stunning sisters posed for a rare selfie with their mother Tina Ann Drew, 61

A rare snap: Earlier this month, the stunning sisters posed for a rare selfie with their mother Tina Ann Drew, 61