Alicia Keys Celebrates Her 'Young King' Stepson Kassem Jr. on His 18th Birthday: 'Totally Unstoppable'

Alicia Keys' stepson is another year older.

On Sunday, Dec. 22, the singer, 43, shared a carousel of photos on her Instagram as she celebrated her stepson Kassem Jr.'s 18th birthday. Keys posted photos of herself and Kassem Jr., who goes by KJ, smiling together throughout the years. She also included a few family photos, as well as a shot of the newly minted 18-year-old as he wore an NYU sweatshirt.

"My amazing young king @yayachronicles !! You are totally unstoppable!! I’m so excited about every moment this year is going to bring!! This is just the beginning of things you can’t even imagine!" Keys wrote in her caption.

"Keep working hard and bringing that light and gratitude, everywhere you go!!!! The blessings of tomorrow will be greater than we can ever imagine today!!! I love you Kassy!! Always your Umi!!! 😍😍😍 Congratulations on NYU babyyyyyyyy!!!!!!!! letssss gooooo!!!!!!!!"

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Related: Alicia Keys Details Son Genesis' Wholesome Reunion with Taylor Swift: 'Is She Gonna Remember Me?'

Keys' husband Swizz Beatz shares son KJ with ex-wife Mashonda Tifrere. He is also dad to son Prince Nasir, 24, whom he shares with former partner Nicole Levy. Beatz is dad to daughter Nicole Dean, 16, with singer Jahna Sebastian.

Keys and Beatz are parents to Egypt Daoud, 14, and Genesis Ali, 9.

During a 2016 appearance on The Ellen DeGeneres Show, where she was promoting her song "Blended Family (What You Do For Love)," Keys opened up about her blended family.

"I feel like the family is such a beautiful and diverse unit and — as we've all experienced — our families come in all different sizes and shapes and versions," Keys explained.

KJ is close with both his mom and his stepmom, who have developed a strong co-parenting relationship.

"I wanted to get to know her because my son was telling me amazing things," Tifrere told PEOPLE of her friendship with Keys, who wrote the forward for Tifrere's 2018 book, Blend: The Secret to Co-Parenting and Creating a Balanced Family.

In June 2024, KJ and his brothers Egypt and Genesis supported Keys at the Tonys in New York City. Hell's Kitchen, a Broadway musical inspired by the singer's life, was nominated for 13 awards.

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