Gwen Stefani and Gavin Rossdale Celebrate Son Kingston's 18th Birthday: 'My First Born Baby Boy'

Gwen Stefani and Gavin Rossdale are toasting to their eldest son, Kingston, turning 18 with sweet Instagram tributes.

Gwen Stefani and Gavin Rossdale are celebrating the 18th birthday of their eldest son, Kingston, with sweet tributes.

On Sunday, the teenager marked his leap into adulthood by having his rockstar parents post commemorative messages -- accompanied by some adorable photos -- to their Instagram pages.

Stefani, 54, used her post to upload dozens of pictures and videos of Kingston throughout the years, ranging from his newborn days to today, set to UB40's "Kingston Town."

"happiest of birthdays Kingston🤍 my first born baby boy :) cannot believe u are 18 today… i love u! 🥰," the No Doubt singer wrote in her post. The former couple -- who split in 2015 -- also share sons Zuma, 15, and Apollo, 10. 

For his part, 58-year-old Rossdale shared a simple carousel featuring numerous pictures of Kingston, starting with a recent snap of the 18-year-old walking under what appears to be a cherry blossom tree while holding up an umbrella. 

"HAPPY BIRTHDAY KINGSTON -18 today and a massive step into your future.so far the best ride of my life and i can't wait to see where you go from here.i have total belief in you and deeply admire the man within.you have grace, charm and humility," the Bush frontman wrote.

He continued, "You are at the wheel of your destiny so choose wisely. your musical talent is nuts and soon the world will hear your heart sing.follow your muse,stay curious and keep creating.i could not love you more than i do.i wish you all the happiness all the health and all the creativity."

Other pictures included in the post show Kingston alongside his brothers and older sister, Daisy Lowe -- whom Rossdale welcomed with his ex, Pearl Lowe -- as well as the teenager enjoying the outdoors and smiling alongside his girlfriend, Lola Albert. 

In response, Kingston took to the comments to thank his dad for the loving post, writing, "best dad ever."

While Rossdale recently opened up about his "debilitating" divorce from Stefani in the 2010s, the pair have kept things amicable in the pursuit of successfully co-parenting their three sons. 

Since their separation, they each have gone on to find new relationships: Stefani with husband Blake Shelton and Rossdale more recently with his musician girlfriend, Xhoana Xheneti.

In April, ET's Cassie DiLaura spoke with Shelton, 47, and the singer shared that despite not having any kids of his own, he has fully accepted his wife's three boys as his children. While he has known the boys since 2014, the singer officially took on the title of stepdad in July 2021 when he and Stefani tied the knot, less than 12 months after he popped the question

Blake Shelton and Gwen Stefani with her three sons, Kingston, Zuma and Apollo, at Shelton's Hollywood Walk of Fame dedication ceremony - Frazer Harrison/Getty Images

Shelton told ET that Kingston, Zuma and Apollo have changed him "in every possible way."

"I learned quickly, not because anything happened, but just, you know, reading the room, you’ve really got [to think], 'I have to take a step back,'" Shelton said of his mindset shift while stepping into the role of stepdad. "When people say it's not about you anymore when you have a kid... I think, if you're doing it right, it's not about you anymore. That's true."

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