Michael Buble was worried he couldn't have children.

The 37-year-old singer is expecting his first child with wife Luisana Lopilato but admitted since he slept with so many women before they met and never got any of them pregnant, he feared he may have been infertile.

He joked to 'Entertainment Tonight Canada': ''I've had sex with a lot of women, near the end I was trying to impregnate them just to see if I could.''

However, he the added: ''But seriously, I went and got tested to see if [I could get someone pregnant]. I was sure it wasn't going to work.''

Michael also revealed he is excited and nervous about becoming a dad and expecting a baby has brought him and his wife closer.

He explained: ''I'm so not ready but who knows who is ever ready for it. I'm more in love with my wife now than I ever was.''

The Argentinian model, 25, has been experiencing some crazy cravings during her pregnancy.

Michael revealed: ''Some women crave pickles or ice cream. My wife wants blood sausages. Sausage made of congealed blood,'' he shares. ''And I promise you, she hated it her whole life and now she said, 'Mike, I want some blood sausage,' and it's like, 'What the hell?'''