The 46-year-old actress welcomed a baby girl with her husband, Dwayne Wade, via surrogate earlier this month after years of fertility struggles. In an Instagram post on Tuesday, Union gushed over the newborn.
Wearing an adorable black onesie with red umbrellas, the baby girl is resting in her mom's arms and getting a kiss on the head in the precious photo.
"?x ☂️ ... this baby smell though?! Heaven ????," Union captioned the sweet shot.
Fellow celebrities were delighted for the new mom, taking to the comments section to congratulate her.
"I can feel your joy," Jada Pinkett Smith wrote. "I'm so happy for you."
Khloe Kardashian, who gave birth to her first child earlier this year, echoed those sentiments, writing, "I am so so happy for you!!! It's the best feeling EVER!!! May God bless you always."
Ellen Pompeo said it was the "best thing in the whole wide world," and Jessica Alba agreed, calling it "literally the best in all the land."
Reese Witherspoon noted that the shot was one of many "precious moments" to come, while Halle Berry declared, "Nothing will ever be better."
Even more star including Yara Shahidi, Niecy Nash and Paris Hilton shared their well wishes too.
The new mom also took to her Instagram Story to share a shot of her baby girl's tiny feet.
The sweet photos come about a week after the couple welcomed their first child together. Wade, 36, has two sons from his first marriage -- Zaire, 16, and Zion, 11 -- and also cares for his 17-year-old nephew, Dahveon Morris. Additionally, the NBA star has a 4-year-old son named Xaiver with his ex-girlfriend.
Union has long since been open about her fertility struggles, specifically in her memoir, We're Going to Need More Wine, which was released last fall.
"I have had eight or nine miscarriages,” she wrote in the book. “For three years, my body has been a prisoner of trying to get pregnant -- I’ve either been about to go into an IVF cycle, in the middle of an IVF cycle, or coming out of an IVF cycle."
Watch the video below for more on the growing family: