Graham also thanked her fans for all their well-wishes on her Instagram Stories. A number of the model's famous friends have publicly congratulated her on the news, including Ellen DeGeneres, Gabrielle Union, Lizzo and Reese Witherspoon.
"OMG! Thank you SO much for your outpouring of love and congratulations!" she wrote. "We couldn't be happier! Love to you all!"
On Thursday, Graham shared a sweet video of her and Ervin revealing the big pregnancy news. The two say "surprise!" and share a kiss as the camera pans down to Ervin rubbing her baby bump.
"Nine years ago today, I married the love of my life," Graham wrote. "It has been the best journey with my favorite person in the world! 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. ?."
Ervin shared his own adorable pictures on Instagram, including one of him holding up their baby's sonogram.
"To my forever love and my daily inspiration," he wrote. "Happy anniversary @ashleygraham These 9 years have played out like a lifetime. I guess it's because my life really started once you came into it. Now that we've made a life together, let's make a life together. I love you and I love us. All of us..."