Brothers Osborne's John Osborne and his wife Lucie Silvas are expecting twins.
The 40-year-old star and his 45-year-old singer-songwriter significant other admitted it was "amazing" when they found out about their twins, after they underwent a "very tough journey with IVF".
Lucie said: "We are so excited. It is such an amazing thing to be in this position to be growing two babies. When you think that you may never have the chance to have children and then suddenly you're going to have two, it's amazing.
"We went through a very long, tough journey with IVF to get to this point.
"We had an embryo transfer where we transferred two embryos thinking that would give us a better chance of getting one [baby], but we got two. I think deep down, we were hoping for two."
John added: "We were."
The star also admitted he has already seen his wife's mother credentials because she has had to be a mum to him a couple of times when he is "being ridiculous" or has consumed one too many beverages.
Speaking in a joint interview with People magazine, he added: "I already know Lucie's going to be an amazing mom, because she has had to be a mom to me a couple of times, when I'm being ridiculous or I've had a few too many drinks.
"She's actually inherently, a very maternal person. I would think any of our friends would say that when they need love and affection and a genuinely non-judgmental person and ear to talk to, they go to Lucie, because she has a very motherly instinct already without having had kids. It's very natural."