People.com reported Mabel Ray Willis weighed in at 9 pounds, 1 ounce when she was born Sunday.
The couple, who have been married three years, "are overjoyed about the newest member of their family. Both mother and baby are healthy and doing beautifully," Willis' representative told People.com.
Willis, 57, has three adult daughters with his ex-wife, actress Demi Moore. He is best known for his work in the "Die Hard" film franchise, as well as the TV show "Moonlighting."
Hemming, 33, is a model and fashion designer.