The trio spent the day taking a stroll through New York City on Friday.
“I can’t believe you have been making me laugh and smile and extremely sleepy for 6 months now!” Teigen wrote on Instagram. “First trip to the park. Best NYC stroll day ever. I love you, my Lu!”
Legend, 37, also took to Instagram, posting an adorable photo of his wife and daughter on a bed, as Luna smiled at the camera.
The caption was simple but no less joyful, with Legend writing “6 months old!” in the caption.
The model, 30, announced her pregnancy on Instagram in October 2015 after revealing that she was undergoing IVF in order to conceive.
The couple, who married in September 2013, announced the birth via social media in April.
“She’s here! Luna Simone Stephens, we are so in love with you! And sleepy. Very sleepy,” Teigen wrote alongside a snapshot of the baby’s weight.
Legend tweeted out the news as well, writing “Our new love is here! Luna Simone Stephens, born on Thursday, the 14th. We couldn’t be happier!”