The sextuplets behind the show "Jon and Kate Plus 8" are now 18 years old.

Aaden, Alexis, Collin, Hannah, Joel and Leah Gosselin celebrated their 18th birthday 15 years after the TLC reality show premiered. The sextuplets were born on May 10, 2004.

The Gosselin family before Jon and Kate's split.

The Gosselin family before Jon and Kate's split. (AP)

The family appeared on "Jon and Kate Plus 8" for 11 seasons. The show ended after 11 seasons following the couple's messy divorce after 10 years of marriage.

Since 2018, Collin and Hannah have lived with Jon while the rest of the sextuplets live with Kate.

Jon honored the sextuplets on his Instagram story by sharing a throwback photo of the family and writing, "Happy 18th Birthday! Today is your birthday we gonna say it loud. I love you, love dad."

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Jon, Hannah Gosselin

Hannah Gosselin and Jon Gosselin arrive to the Sugar Factory. (Robin Roslund)

Jon, Hannah Gosselin

Jon Gosselin and Hannah Gosselin celebrate her 18th birthday at the Sugar Factory. (Robin Roslund)

Kate didn't appear to publicly celebrate the sextuplets' birthday.

One of the sextuplets celebrated her birthday in a big way. Hannah Gosselin released a new skincare line, Gosselin Girl.

Jon took Hannah and four of her friends to the Sugar Factory to celebrate her 18th birthday and the launch of her brand.

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Hannah Gosselin

Hannah Gosselin arrives to her 18th birthday celebration. (Robin Roslund)

The group arrived in a white Phantom Rolls-Royce.

"Oh the Rolls Royce was amazing," Hannah told Entertainment Tonight. "I was like, ‘Oh, new dream car,’ and it had an all orange interior. It was gorgeous. I went to Miami, and my four best friends joined me down there, and we threw this big birthday thing at The Sugar Factory. It was amazing. I was so astonished by, like, I really didn't think it was gonna be that big, and I was so excited."

Hannah also spoke about pursuing her "big dream" of being in the business world.

Hannah Gosselin

Hannah Gosselin launches a skincare brand, Gosselin Girl, on her 18th birthday. (Robin Roslund)

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"I am dropping a product line, and it is a bunch of skincare, and I'm very excited about it," she says. "Being 18, I can vote now, and I can drive my car out of state."

"I've always had this big dream of being the business manager, like, I want to own my own business and succeed because of me," she adds.

Hannah also noted that she and her siblings all wished each other a happy birthday privately.

"Oh, 100%, I miss my siblings," she told ET. "I mean, we all do share, like, the same birthday. It's a big day for all of us today. As soon as I woke up they texted me happy birthday and I sent them a happy birthday text back."