Happy birthday, Maxwell!
Jessica Simpson's daughter turned five years old on Monday, and celebrated with the most epic mermaid party!
WATCH: Jessica Simpson's Daughter Maxwell Is a Little 'Cowgirl' in New Horseback Riding Pic
"My baby Maxwell is 5 years old today. She makes everyone's life mermaid magical," Simspon captioned a cute family pic -- with Maxi dressed as a mermaid -- on Instagram. "Happy Birthday to our fairytale princess. Mommy, Daddy, and Ace love you with our "holy hearts" (as Max would say) #MerMax #MAXIDREW #canyoube5forever."
RELATED: Jessica Simpson Smooches Eric Johnson While Posing With Their Kids in Gorgeous Family Easter Portrait
The 36-year-old fashion designer later shared a photo of Maxi's "first splash."
"First Splash #MerMax5 #MAXIDREW," she wrote alongside the sweet baby picture.
WATCH: Jessica Simpson's Daughter Maxwell Has Officially Become Her Doppleganger -- See the 'Mad' Pic!
Missing from Maxi's birthday festivities appears to be her "cool" cousin, Bronx.
See more in the video below.