KimberlyStewartBaby082211.jpgKimberly Stewart gave birth to a baby girl Sunday and now her dad, Rod Stewart, is sharing his excitement over his first granddaugther.

"My joy is indescribable," the 66-year-old singer told People. He also told the mag it was one of the happiest days of his life.

The actress/model gave birth to her first daughter in Los Angeles on her 32nd birthday.

Kimberly's ex, actor Benicio del Toro, 42, is the baby daddy. The two haven't named their daughter yet, but the Sin City star is said to be thrilled at the new addition to his family.

Back in April, Benicio's rep told People, "Benicio is the father and is very supportive. Although they are not a couple, they are looking forward to the arrival of the baby."

Congrats to both the Stewart and del Toro clans!