Little Clover Elizabeth, who is the couple's fourth child, was born on Monday (15Aug11) at Los Angeles' Good Samaritan Hospital.
The proud father tells People.com, "Ruve gave birth to a beauty! 8½ lbs. and 21 inches with thick dark hair like her gorgeous Mommy... We are so blessed."
The baby girl joins the McDonoughs' kids London Jane, 19 months, Catherine Maggie, four, and five-year-old Morgan Patrick.
There has been somewhat of a baby boom in Hollywood in recent days - Jessica Alba and Tina Fey both gave birth during the past week and Kevin Federline became a father for the fifth time on Monday (15Aug11). Meanwhile, Hilary Duff and Roselyn Sanchez both announced they are pregnant.