Gwen Stefani’s oldest son Kingston looks all grown-up as she celebrates rocker teen’s 15th birthday with sweet photo

GWEN Stefani's oldest son Kingston looked all grown-up in a sweet Instagram photo she posted to celebrate the rocker teen's 15th birthday.

The shoutout featured the birthday boy sporting long shaggy hair while strumming a guitar.

She captioned the pic: "happy 15th b day to my beautiful boy @kingsrossdale_ love u mom gx"

The Voice alum shares Kingston and his two younger brothers, Zuma, 12, and Apollo, 7, with ex-husband Gavin Rossdale.

Fans were quick to point out the resemblance between Kingston and his musician father in the comments.

One fan writing: "Oh my... he sure resembles Gavin. So sweet."

And another: "Splitting image of his dad, WOW!"

Some even comparing the teen's appearance to the late Kurt Cobain.

Gwen was married to the Bush vocalist for 13 years before their split in 2015.

The Spiderwebs singer is currently engaged to country superstar, Blake Shelton whom she met when they both sat on the panel of the seventh series of NBC's singing competition The Voice in 2014.

A year later, when both of their hearts were broken from their divorces, they began a romantic relationship.

Blake was also finalizing his divorce with his ex-wife Miranda Lambert after a four-year marriage.

Last year, the Minimum Wage singer proposed to Gwen at his ranch in Oklahoma, where the couple spent the majority of the coronavirus lockdown period together.

A source previously told PEOPLE that the couple want to tie the knot quickly, as they are "ready to get married" after a short engagement.

"This won't be a long engagement. There is a reason why Blake proposed now," the insider revealed. "They are both ready to get married."

The source added: "They don't want a huge wedding. They want their family and close friends to attend and that's it."

Last month, Gwen herself opened up about the big day, virtually telling the Late Night With Seth Meyers show that she is yet to pick a wedding singer.

Joking she hoped close friend and fellow Voice coach Adam Levine would be up for it, she said: "I definitely would love to have Adam sing at our wedding."

However, the former No Doubt band member said said she felt like they may ditch the wedding band for a "playlist" as part of their "simple" day.

She doesn't want dozens of celebrities in attendance, as she revealed it will likely "just be family."

"It's gonna be like, my mom and my dad and just literally gonna be just family," she explained. "We are looking forward to that though. It's gonna be fun."

"But it's not gonna be a big, like, you know, it's not like the queen and king are getting married or something," Gwen added.