Kelly Clarkson is a very proud new mother. The 32-year-old singer and husband Brandon Blackstock welcomed daughter River Rose on June 12. Clarkson tweeted, "Brandon and I are on cloud 9!!" shortly after the birth, and posted the first photo of the newborn Friday. "Here is our beautiful baby girl River Rose; 6 lbs, 6 oz, 18 inches, and the greatest thing on the planet :)," the original "American Idol" winner wrote. River Rose is the couple's first child together; Clarkson is also stepmother to Blackstock's son and daughter from his previous marriage. The happy news comes amid rumors that Blackstock was unfaithful to the singer.