Andy Cohen's WWHL Staff Sings His Son Benjamin 'Happy Birthday' as Boy Turns 1 — Watch

Andy Cohen‘s son Benjamin Allen was showered with love for his first birthday!

On Tuesday, PEOPLE’s reigning “Cutest Baby Alive” celebrated his big day with a birthday bash thrown by the staff of his dad’s talk show, Watch What Happens Live with Andy Cohen.

The event included cake, balloons, party hats and one particularly sweet moment caught on camera and shared to the show’s social media accounts — a touching “Happy Birthday” sing-a-long.

Ben appeared to be in good spirits during the song, curled up in Cohen’s arms. The little boy wore a blue sweatshirt with the phrase “One Year Old” stitched across the front, in the style made famous by designer Rachelle Hruska MacPherson’s label, Lingua Franca.

“Cutest baby alive & Bravolebrity-In-Training!” a WWHL staffer wrote. “Happy Birthday Ben!”

“Thanks for a great party guys!” Cohen, 51, commented.

Earlier in the day, Cohen shared a touching message to baby Ben on Instagram, captioning a black and white photo (taken by pal John Mayer) of the father-son duo moments after the boy’s birth.

“One year ago tonight, I sat alone in a hospital room with my newborn son pondering our future,” Cohen recalled. “I didn’t know then how his smile would brighten my day, what simple joy each new progression of his growth would bring, and most of all what a lovely boy he would become.”

“I am so grateful to my surrogate in California who made this all possible, and for every day of our first year… and can’t wait for the next,” Cohen added. “Happy Birthday sweet little Ben. #dada.”

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Cohen’s message was met with love from many of his famous friends, including Ellen Pompeo, Naomi Campbell, Bob Saget, Sandra Bernhard and Gary Janetti.

“Feels like yesterday,” wrote Kelly Ripa.

“There really is nothing sweeter,” said Donny Osmond. “Happy birthday Ben!”

WATCH: Andy Cohen’s Son Benjamin Is PEOPLE’s Cutest Baby Alive 2019!

Many Real Housewives — past and present — also sent love. Bravo stars such as Teresa Giudice, Luann de Lesseps, Kandi Burruss, Lisa Rinna, Yolanda Hadid, Gizelle Bryant, Dorit Kemsley, Sonja Morgan and many more sent well wishes to baby Ben.

“Happiest 1st Birthday sweet baby Ben!!” said Real Housewives of New Jersey star Margaret Josephs. “Looking forward to watching you grow🎂👶🏼💋💕👧🏼.”

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Over the past year, Cohen has posted plenty of adorable pictures and videos of Ben on social media. The first photos appeared on PEOPLE, in a cover story shot just a week after Ben’s birth on Feb. 4, 2019.

“I was in the delivery room. I had been hoping that he would have a full head of hair, and he really overdelivered,” Cohen joked at the time. “That was the first thing you see, the head of hair coming out. And I was amazed.”

Almost 10 months later, Cohen opened up to PEOPLE about how much he has been enjoying fatherhood, despite the ups and downs.

“It can feel overwhelming, but when he looks back at me and smiles or laughs at something I say, everything feels right,” he said.

As for Ben’s other birthday celebrations, on Monday’s episode of Cohen’s SiriusXM radio show, Andy Cohen Live, the TV personality revealed he threw an official party for his son on Sunday.

“I had a join first birthday slash Super Bowl party for Ben,” Cohen said. “It was nice, it was a great party. I had family, I had friends. It was lovely.”

“The headline of my thing was that my son — who was downstairs from 4:30pm until 7:30, being passed around from person to person — didn’t flinch,” he added.