Benjamin Travolta arrived Tuesday at an undisclosed Florida hospital. He weighed 8 pounds, 3 ounces.
The couple and their daughter, Ella Bleu, 10, "are ecstatic and very happy about the newest member of the family," family spokeswoman Samantha Mast said in a statement. "Both mother and baby are healthy and doing beautifully."
This is the couple's third child. Two-time Oscar nominee Travolta, 56, and Preston, 48, who were married in Paris in 1991, suffered the death of their son Jett, 16, in January 2009 after a seizure during a family vacation in the Bahamas.
The couple announced Preston's pregnancy in May on her and Travolta's websites, noting then that some sources "say that we are having twins. It's a wonderful idea, but it's untrue. We are just having one."
There was no update on Benjamin yesterday afternoon at Travolta.com or KellyPreston.com.