'Sister Wives' Star Janelle Brown Celebrates Son Gabe's 21st Birthday: 'Where Did The Time Go?'

Janelle and Kody Brown, Gabe Brown
Janelle and Kody Brown, Gabe Brown

Gabe Ginsberg/FilmMagic; Janelle Brown/Instagram

Janelle Brown's kids are all grown up!

On Tuesday, the Sister Wives star celebrated son Gabriel's 21st birthday with a sweet Instagram post.

Decorated with a "happy birthday" sticker and with Kool & the Gang's "Celebrate Good Times" as the soundtrack, she shared a video of the two out to eat, captioning the clip, "Gabe is 21!!! Gabe is 21!!!"

"My Gabe is 21! Where does the time go !" she captioned the post. "Had so much fun celebrating at @cucina_rustica_sedona last night. Happy Birthday honey! I wish all the best for you ❤️."

In the clip, Gabe blows out a birthday candle stuck in a scoop of ice cream served in a martini glass and smiles at the camera.

Janelle shares all six of her children with husband Kody Brown.

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RELATED: 'Sister Wives' : A Guide to the Polygamous Family

Kody and Janelle share Savannah, 17, Gabriel, Garrison, 23, Maddie, 26, and Logan, 28. Kody has four other children with his two current wives — Meri Brown and Robyn Brown — as well as six kids with ex-wife Christine Brown.

In a Sister Wives episode that aired last February, Kody spoke about his relationship with Janelle, noting they were "not in sync."

"We don't partner really well but we actually just are able to have a marriage that's, if you will, lower in attachment," he continued. "I don't even know. We're good friends, we get along well. It's more of a, like, just a committed relationship."

Janelle Brown
Janelle Brown

Gabe Ginsberg/FilmMagic Janelle and Kody Brown

Addressing whether he's still "in love" with Janelle, Kody said he has "love" for her but couldn't declare anything beyond that at the time.

Janelle is Kody's second wife. The pair have been married since 1993.

Through their plural marriage, Kody is also still spiritually bound to first wife Meri Brown and fourth wife Robyn Brown. But Kody's relationship with Meri, in particular, is no longer romantic.