John Travolta and Kelly Preston's baby boy will arrive in about three weeks, and they will name him Benjamin, John tells Star magazine.
John, 56, and Kelly, 48, announced they were expecting in May.
"It's impossible to keep a secret ... especially one as wonderful as this," they said in a statement. "We want to be the first to share this great news with everyone that we are expecting a new addition to our family."
They have a daughter, Ella Bleu, 10, and lost their son Jett at the age of 16 last year.
See photos of a glowing Kelly showing off her baby bump here.