Lacey Chabert attends the 7th Annual Milk + Bookies' Story Time Celebration at California Market Center on April 17, 2016 in Los Angeles. Credit: Allen Berezovsky/Getty Images

Party of three! Lacey Chabert welcomed her first child, daughter Julia Mimi Bella Nehdar, on Thursday, September 1, and shared a pic of her baby girl on Instagram.

"And then my soul saw you and it kind of went, 'Oh, there you are. I've been looking for you,'" the former Party of Five star captioned the sweet pic on Thursday, September 8.

"#TBT to the best day of my life. One week ago I became a mom to this precious angel. Julia Mimi Bella," she continued. "Julia, you are my heart's deepest dream come true. I love you more than I could ever say! Welcome to this big beautiful world sweet girl!"

As Us Weekly exclusively reported, the Mean Girls actress, 33, prepped for her first child with husband David Nehdar by creating a chic nursery for little Julia that featured a pink-and-gray color scheme.

Chabert, who married Nehdar in 2013 at a star-studded wedding in Los Angeles, revealed her pregnancy news on Twitter in February, posting a cute photo of her Chihuahua, Kitty, wearing a tiny shirt that read, "My mom is having a baby & all I get is this silly shirt."

"Kitty doesn't seem as excited about this as we are," Chabert captioned the pic. "I'm pregnant!!! My husband and I are thrilled & so thankful."

The new mom's celebrity pals offered up their well wishes on Thursday, with Michelle Trachtenberg commenting on Chabert's Instagram pic, "Wow. What a gorgeous beautiful angel. Congratulations, this is a role you were always meant for my friend!! So much love to you and your family."

"HUGE congrats!" Sara Rue tweeted. "She is absolutely perfect!!! Enjoy every terrifying, beautiful, gross, silly, exhausting second of it!!"

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