The 34-year-old model and television personality and 41-year-old singer posted tributes on social media and threw an at-home party for their daughter, Luna, on her birthday Tuesday.
Teigen had nothing but praise for Luna on Twitter. She shared a photo of her daughter wearing a two-piece swimsuit and a crown.
"I was not prepared for a love like this. you are smart, funny, chaotic and full of love and empathy. happy 4th birthday to my tiny queen," Teigen captioned the post.
Teigen posted the same picture on Instagram, writing, "happy 4th birthday to the queen of our household. I could have never prayed for a better little being."
Legend also paid tribute to Luna on Instagram.
"Happy 4th birthday to our beautiful Luna! I'm so happy I get to be your father, teacher, friend," he wrote.
Legend later shared a photo that showed Luna wearing a yellow princess dress and white cape during her birthday party at home. Teigen, Legend and their family are self-isolating amid the coronavirus pandemic.
"Luna's living her best birthday life. Mommy decorated. No preschool friends were able to come, but they sent video messages and she was thrilled. Good memories for her during this strange time," Legend wrote.
Socialite and businesswoman Paris Hilton, Real Housewives of Beverly Hills star Garcelle Beauvais and actresses Milla Jovovich and Stacy Keibler were among those to wish Luna a happy birthday in Instagram comments.
"Awww Happy Birthday sweet little mama," Beauvais wrote.
"Perfect little combo of mama and papa! Happy Birthday beautiful girl!" Jovovich added.
"Happy birthday Luna!!!! You are such an amazing little bring," Keibler said.
Teigen and Legend married in September 2013 and also have a son, Miles, who turns two years old in May. Teigen discussed her kids in the spring-summer issue of Glamour U.K. magazine.
"Luna loves make-up; she loves being 'girlie,' whatever that means now," the model said. "She likes wearing princess dresses and lipstick. If she wants to wear lipstick every now and then and that makes her happy, I say 'go for it!'"