Dierks Bentley finally has a son. The award-winning country singer and his wife, Cassidy, welcomed their third child late Wednesday night, a baby boy named Knox. "Well . . . our boy Knox is here! about to have the best tasting cold beer of my life! so proud of my wife. she rocked it. crazy stuff. #beerme," Bentley, 37, tweeted after the birth. He added: "Mad respect for doctors, nurses and everyone at hospitals. can't believe y'all do that day in and day out." Dierks and Cassidy are already parents to daughters Evie, 4, and Jordan, 2.