Paris Hilton recently revealed that her family didn’t know about her baby boy, Phoenix Barron, until a week after his birth

PHOTO: DENNIS GOCER/SHUTTERSTOCK

Kathy Hilton is soaking up special moments with her newest grandbaby.

The 63-year-old and daughter Paris Hilton pose with Paris’ baby boy Phoenix Barron in a new photo, with Kathy standing behind her daughter and giving Phoenix a kiss on the head while Paris cradles her son.

Phoenix is dressed in a white onesie and matching white hat in the serene shot, while Kathy wears a mint-colored blouse.

The new family photo comes shortly after Paris, who welcomed Phoenix with husband Carter Reum in January, revealed that Kathy didn’t know about her new grandson until he was “about a week old.”

“Not even my mom, my sisters, my best friend knew until he was over a week old,” Paris shared on last week’s episode of her iHeartRadio podcast This Is Paris. “It was really nice to have that with Carter, be our own journey together. I just feel like my life has been so public, and I’ve never really had anything be just mine.”

Paris Hilton, husband Carter Reum, and son Phoenix Barron Hilton Reum. DENNIS GOCER/SHUTTERSTOCK

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The “Stars Are Blind” singer talked about how her life in the public eye has been “invaded” many times, while the entrepreneur, 42 — who is already a dad to a daughter — “has always been a really private person.”

“So when we were talking about it, I really felt that I wanted this journey to be for us only,” Paris explained, noting it was “hard to keep that in.”

“Because we were so excited and wanted to tell our families, but we were just nervous because if you tell a person, then they tell someone, and all the sudden, it’s in TMZ or Page Six, and I’ve had enough of my life like that,” she continued. “So Carter and I literally made a pact together that we would not tell anyone, and no one knew until just recently.”

Paris Hilton and Kathy Hilton. CHARLES SYKES/BRAVO/GETTY

“When I introduced my mom to our baby boy, it was amazing to see the look on her face,” Paris shared. “She was so surprised — just the look on her face, it was priceless.”

Kathy previously told PEOPLE exclusively that she and husband Rick Hilton “are over the moon” after the birth of their latest grandson.

“Paris and Carter, we know you are going to be the most amazing parents,” Kathy said in a statement to PEOPLE. “We are so thrilled for you both! Thank you for this perfect addition to our ever-growing, beautiful family.”