The actress, 50, marked daughter Eloise's 10th birthday on Instagram Tuesday with a heartfelt tribute to her youngest child.
"Yesterday was our sweet angel Eloise's 10th birthday..... we love you so much girlie," Richards wrote alongside a collage of photos of Eloise. "You are a ray of ☀️ & you have the biggest heart. Always so happy & love life. You have taught us so much."
"Happy happy birthday 🎂. I'm very blessed to be your mommy. I love you. ❤️," she added.
Eloise received additional birthday wishes in the comment section of the post from several of her mom's famous followers, including Real Housewives of Beverly Hills stars Dorit Kemsley and Camille Grammer, Real Housewives of Orange County's Shannon Beador and Selling Sunset star Chrishell Stause.
Richards adopted Eloise in 2011 and now shares her with husband Aaron Phypers. She is also mom to daughters Sami, 17, and Lola, 15½, whom she shares with ex Charlie Sheen. She and Sheen, 55, married in 2002 and split three years later, and she married Phypers, 48, in 2018.
In a recent interview with Parents.com, the Bravo alum said that Eloise — who was diagnosed with a deletion in chromosome 8, a chromosomal disorder that causes developmental delays — is "a sweet little angel and the happiest little girl, and the littlest things make her so happy."
"She communicates in other ways with our animals," Richards said, sharing that they nicknamed Eloise their "animal whisperer."
Denise Richards/Instagram Denise Richards with her daughters
In February 2019, Richards opened up to PEOPLE about raising her daughters — "I'm most proud of raising my kids, especially in a time that is very different from how I was raised," she said — as well as the unique set of challenges she has with Eloise.
Richards recounted when she first noticed that Eloise wasn't reaching typical milestones for babies.
"She wasn't able to sit up on her own for a very long time, and she didn't start walking until she was 2, and that was with physical therapy," she said. "She can only say a handful of words."
Denise Richards Instagram
However, Richards has remained optimistic. "Every child is different," she told PEOPLE at the time. "You take care of your children no matter what is going on with them."