Paris Hilton Says Mom Kathy Hilton Is 'Obsessed' with Visiting Baby Son Phoenix 'Unannounced'

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Charles Sykes/Bravo/Getty Paris Hilton and Kathy Hilton

Paris Hilton's mom Kathy Hilton is "obsessed" with her new grandson.

During an appearance on The Tonight Show Starring Jimmy Fallon on Monday night, the new mom, 42, gushed about life with 2-month-old baby Phoenix Barron Hilton Reum, whom she shares with husband Carter Reum.

"He is such an angel, he's the best," Paris said of her newborn son, beaming that she can't stop staring at him. "I'm just so obsessed with him, I feel my heart is going to explode."

Equally obsessed? Paris' mom Kathy, who Paris said is loving being a grandma. "[She's] obsessed with showing up all the time, unannounced," Paris joked. "I'm like, 'Mom, when did you get here?' 'Oh, I've been here for hours!' "

RELATED: Kathy Hilton Poses with Grandson After Paris Says She Didn't Know About Baby Until After Birth

Of course, Kathy, 64, has experience as a grandma. Daughter Nicky Hilton Rothschild, 39, shares three kids with husband James Rothschild: an 8-month-old son and daughters Lily-Grace Victoria, 6, and Theodora "Teddy" Marilyn, 5.

"Paris and Carter, we know you are going to be the most amazing parents," Kathy said in a statement to PEOPLE in January, upon news that Paris and Carter had quietly welcomed Phoenix via surrogate. The Real Housewives of Beverly Hills star added that she and husband Rick Hilton "are over the moon" after the birth of their grandson. "We are so thrilled for you both! Thank you for this perfect addition to our ever-growing, beautiful family."

MICHAEL TRAN/AFP via Getty

Elsewhere in her interview on The Tonight Show, Paris was asked what sort of playlist Phoenix likes — Fallon noting Paris' career as a DJ.

"Well, I actually sang his favorite lullaby, which is my song 'Stars Are Blind,' " the artist said, prompting cheers from the audience. "He has great taste in music."

That prompted Fallon to bring up Miley Cyrus' News Year's Eve special on NBC where Cyrus brought Hilton — along with Sia — out to sing the song. "I love her so much. She is so cool," Hilton said of Cyrus, who said is a fan of the song. "She is epic."

RELATED: The Biggest Revelations from Paris Hilton's New Memoir, Including How Demi Lovato Helped Her Overcome Trauma

She went on to discuss her new book, Paris: The Memoir, noting how she was ready to "tell my truth" in the narrative, which details things like her experience living with ADHD and PTSD from the abuse she experienced in boarding school.

Paris also discusses her relationship with mom Kathy in the book. Among the things that have grown out of the their bond includes Hilton's love for pranking people. She even has a separate phone for making prank phone calls.

"My mom taught me," Paris confessed, she said of the "prank-calling afterparty" that they will often have at the end of a night. "She's the queen of prank calls. She's so good at it."

Hilton and her husband welcomed son Phoenix on Jan. 16, 2023.

"It's always been my dream to be a mother," Paris told PEOPLE at the time, adding, "I'm so happy that Carter and I found each other."

The pair, who married in late 2021, kept the news of their baby boy to themselves for over a week. Paris announced Phoenix's arrival eight days after his birth on Instagram with a close-up photo of her holding his hand, writing, "You are already loved beyond words 💙."

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In February, Paris shared the first photos of her son and his name, which holds an extra special meaning. "From the moment I laid eyes on him, my heart felt so full," she said on her iHeartRadio podcast, This is Paris. "I feel like my life is so complete now. I always wanted to be a mom."

The Tonight Show Starring Jimmy Fallon airs weeknights (at 11:35 p.m. ET) on NBC.