Maria Shriver Celebrates 60th Birthday With Low-Key Yet Star-Studded Party

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Kris Jenner wasn't the only one ringing in a birthday on Friday!

Maria Shriver certainly knows how to party!

The journalist turned 60 on Friday, and she celebrated with a laidback bash at the Montage Hotel in Beverly Hills, California.

WATCH: Kris Jenner Celebrates 60th Birthday With Gatsby-Themed Soiree

While the party itself was low-key, the A-list guests in attendance made her night one to remember. Shriver was joined by many of her celebrity pals, including Oprah Winfrey, Tom Hanks, Stevie Wonder, Rob Lowe and Sean Hayes.

An eyewitness tells ET that although ex-husband Arnold Schwarzenegger wasn't there, three of their four kids together -- Katherine, 25, Patrick, 22, and Christopher, 18 -- were present. Inside the party, guests were treated to appetizers, cupcakes displaying vintage photos of Shriver and a photo booth, according to the source. 

Later in the night, Wonder took the stage with his house band to honor Shriver by singing "Happy Birthday" and "Signed, Sealed, Delivered I'm Yours." Winfrey snapped a photo from the special moment, sharing it with fans on Instagram following the party.

PHOTOS: Arnold Schwarzenegger Spends His 68th Birthday With Maria Shriver

"Stevie Wonder singing 'Happy Birthday to you!' to my dear @mariashriver," she wrote. "A phenomenal woman and friend since our 20's."

Patrick and Katherine also took to social media, sharing photo booth pics from inside the bash.

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Before the party, both posted photos of their mother with sweet messages.

"Happy birthday to this beautiful person," Patrick wrote. "Most hilarious and coolest mother I could ever ask for! Love you so much m dog."

"Today is your day!!! Happy happy birthday to my amazing mama who is the smartest, best, most loving woman I know," Katherine shared. "You inspire me every day and its been amazing to watch you grow and blossom into the stunner you are! Cheers to the only woman who can outdo a group of 20 year olds in her leather catsuit!! Love you tons!"

WATCH: Arnold Schwarzenegger Calls Couples Therapy With Maria Shriver the 'Biggest Mistake' He's Ever Made

While their sister, Christina, couldn't make it to the party, the 24-year-old still took time to dedicate an Instagram post to her mom, captioning a throwback photo, "HBD to goddess!!!!!!!!! Best momma anyone could ever ask for."

Shriver isn't the only one who celebrated their 60th birthday on Friday. Kris Jenner pulled out all the stops with a Great Gatsby-themed bash in West Hollywood, California. The Keeping Up With the Kardashians "momager" was surrounded by family and friends dressed in elegant '20s-inspired ensembles at the fancy fête held at the The Lot.

Watch the video below to hear more about Jenner's extravagant celebration.