Kardashian, 39, and Thompson, 32, filed paperwork earlier this year to change Tatum’s last name from Kardashian to Thompson, which was granted on Thursday, August 31, according to court documents obtained by Us.
Under California law, parents can choose if their new baby will have either the mother’s or father’s last name (or an amalgamation of the two) upon birth.
Us previously confirmed in June that Tatum, now 13 months, initially had the Kardashians star’s surname. Kardashian and Thompson dated on and off between 2016 and 2021, splitting for good after the reality TV star learned that he cheated on her with Maralee Nichols and fathered son Theo.
Kardashian and the Los Angeles Lakers athlete — who also coparent 5-year-old daughter True — welcomed baby No. 2 in July 2022 via surrogate. (Thompson is also father to sons Prince, 6, and Theo, 20 months, whom he shares with Jordan Craig and Nichols, respectively.)
After Tatum’s arrival, Kardashian and Thompson kept his moniker under wraps. “At first, I really did not know what I was going to name him,” she said during an April appearance on The Jennifer Hudson Show, revealing she planned to go with a “T” name like True and Tristan. “I wanted to meet him and feel him out a little bit. And so, at first, he didn’t have a name. Then, he’s been named, but I’ve been waiting for the premiere of our show and I didn’t know it was going to be this far out, so now, if my daughter outs me, I’m screwed.”
Months later, Kardashian and Thompson came together to celebrate Tatum’s first birthday with an elaborate outer space-themed bash.
“I am a firm believer in that God gives you what you need and I needed you. God knew my heart needed you,” Kardashian wrote via her Instagram last month hours before the party. “I needed your sweet and precious smile. I needed your angelic spirit. I needed a love only you could give me. I needed my son.”
She continued at the time: “I am so proud to be your mommy. So proud of the love and laughter we have in our house. So proud of your beautiful, gentle, loving, infectious spirit. You light up every single room. There’s no denying that everyone smiles when they look at you! Especially True, she is so proud to call you hers.”