The 29-year-old rugby player and Saturdays' singer Una, 33, are already parents to two-year-old daughter Aoife Belle.
He told OK!: "I don't actually know the specific date she's due but it'll be some time in February I think."
Ben also confessed he thinks his wife suits being pregnant and we have to agree!
He continued: "It's gone round really quickly. We haven't really done much together, she's done most of it and she's quite good at dressing for the occasion.
"She's pretty big at the moment but she's looking brilliant, she really suits it."
Before Christmas it was revealed the couple are having a boy, and Ben admitted his excitement about welcoming his first son.
He said: "We're both really excited. With is being a baby boy as well, I'm obviously delighted and I can look forward to Sunday league football. I'll do my best to embarrass him as much as I can.
"Aoife understands and [she understands] that something's growing in mummy's tummy."