The model and her director husband welcome their first child, a son, on Jan. 18.
"At 6:00pm on Saturday our lives changed for the better," she wrote on her Instagram story. "Thank you for all your love and support during this incredible time." She has yet to reveal her son's name.
Graham revealed the sex of her baby on the "The Ellen DeGeneres" show in November. "I'm having a boy! I'm going to be a mommy to a boy!" she announced to the audience.
The 32-year-old announced she was pregnant on Aug. 14 via social media.
“Nine years ago today, I married the love of my life. It has been the best journey with my favorite person in the world!” Graham wrote on Instagram at the time. “Today, we are feeling so blessed, grateful and excited to celebrate with our GROWING FAMILY! Happy anniversary, @mrjustinervin Life is about to get even better.”
Since her exciting announcement, Graham has been proudly showing off her growing baby bump online, including many nude snaps and a video displaying her stretch marks.
She even appeared on the cover of a Vogue magazine issue that celebrated pregnancy, motherhood and love.
"A VOGUE COVER!!! — celebrating inclusivity, mothers, pregnancy and love — is so surreal. I have dreamed of this moment my entire career since I was a catalogue model living in Nebraska two decades ago," she wrote.
"Thank you @voguemagazine and #AnnaWintour for embracing a conversation around pregnancy and motherhood, which can be both incredibly exciting and also isolating. The community and support I have discovered along the way has been incredible, and to share this monumental moment with my son and husband in the pages of Vogue could not feel more special."