Ashlee Simpson Ross Celebrates 'Kindest and Coolest' Son Bronx on 14th Birthday: 'My Grown Boy'

Ashlee Simpson Ross Celebrates 'Kindest and Coolest' Son Bronx on 14th Birthday: 'My Grown Boy'
Ashlee Simpson Ross Celebrates 'Kindest and Coolest' Son Bronx on 14th Birthday: 'My Grown Boy'
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Ashlee Simpson Ross/Instagram

Ashlee Simpson Ross is one proud mama on her oldest baby's birthday.

On Monday, the mom of three, 38, shared a sweet photo on Instagram where she smiles widely next to her teenage son, Bronx, on his 14th birthday.

"BRONX happy birthday my grown boy," the singer wrote in the photo's caption. "Can't believe you are 14. You are the kindest, and coolest. I am so lucky to be your mom."

Sharing a selfie of the two together, dad Pete Wentz, also wished his son a happy birthday on his Instagram Story. "Happy birthday to my guy. Lucky to be your dad," he wrote.

Bronx also got some birthday love from aunt Jessica Simpson.

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https://www.instagram.com/p/CkUH48DvX3G/ ashleesimpsonross's profile picture ashleesimpsonross Verified Happy birthday Ziggy Blu can’t believe you are 2! We love you so much Credit: Ashlee Simpson Ross Instagram
https://www.instagram.com/p/CkUH48DvX3G/ ashleesimpsonross's profile picture ashleesimpsonross Verified Happy birthday Ziggy Blu can’t believe you are 2! We love you so much Credit: Ashlee Simpson Ross Instagram

Ashlee Simpson Ross Instagram

RELATED: Ashlee Simpson Ross' Son Bronx, 13, Looks All Grown Up in 'London Dinner Date' Photo with Mom

On Sunday, the fashion designer, 42, shared a post on Instagram in honor of her nephew turning 14. In the snap, Simpson posed with Bronx as the pair smiled in front of a frosted cookie cake.

"Happy 14th Birthday BX!!! I love you SO very much. You are a gift to everyone who is lucky enough know you, love you and be loved by you," Simpson wrote. "Being your Aunt…has been…WILL ALWAYS BE…one of the most precious blessings of my life! Thank you for being YOU! 💚🎉💫"

Along with Bronx, Simpson Ross shares daughter Jagger, 7, and son Ziggy Blue, 2, with husband Evan Ross.

Ashlee Simpson Ross family photo at bday party
Ashlee Simpson Ross family photo at bday party

Courtesy of Ashlee Simpson Ross

Last month, Simpson Ross shared a sweet family photo on Instagram featuring all three of her kids and her husband as the group celebrated Ziggy Blu's second birthday.

In the snap, Simpson Ross held Ziggy as daughter Jagger stood in front of her, son Bronx on her side and her husband behind her. The group smiled for the camera, which featured Jagger in a blue Halloween costume.

Ashlee also shared another picture of Ziggy from his celebration, as well as a photo of the toddler's Halloween-themed birthday cake complete with little creatures, a black cat and mini pumpkins.

"Happy birthday Ziggy Blu can't believe you are 2! We love you so much 🥳," wrote Ashlee.