The former prison officer - nicknamed Screwbo on the show - says she found out after doing a pregnancy test during a trip to the supermarket with her husband.
She told The Sun: “I went and did it in the toilet while he was getting all the food.
“I came out and went, ‘Yep — I’m pregnant’. It wasn’t planned.”
It will be the 36-year-old's third child with hubby Craig, although she admits the news initially left her shocked and upset.
"But they were really good about it. I was going to go on tour solo at the end of October — but I have managed to move it until January.”
But Sam - who is ten weeks pregnant — says she and Craig couldn't be happier that she is expecting again.
“He thinks it’s a New Year’s Eve baby and he could be right. I’ve always wanted three kids.”
Sam has since taken to Twitter to confirm the news, posting a snap of her first scan, which she captioned: 'Meet Peanut!!'
Hey everyone...... Meet peanut!!! :-) pic.twitter.com/QuUzO6yNaj
— Sam Bailey Official (@SamBaileyREAL) March 6, 2014
Congrats to them both!
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Who's the mumma? Sophie Hunter Who's the daddy? Benedict Cumberbatch Baby ETA: 2015 Interesting fact: Could this be the year Benedict becomes a father AND scoops an Oscar nomination? Time will tell...
Who's the mumma? Zooey Deschanel Who's the daddy? Jacon Pechenik Baby ETA: Later this year Interesting fact: This will be the 'New Girl' actress's first baby, which she says she is "over the moon" about.
Who's the mumma? Abbey Clancy Who's the daddy? Peter Crouch Baby ETA: 2015 Interesting fact: The 'Strictly' champ broke her baby news on her official Twitter page.
Who's the mumma? Keira Knightley Who's the daddy? James Righton Baby ETA: Spring 2015 Interesting fact: Keira and James tied the knot in May 2013. This will be their first baby.
Who's the mumma? Katherine Jenkins Who's the daddy? Andrew Levitas Baby ETA: Late 2015 Interesting fact: The couple shared their baby joy with an adorable snap on Instagram of a pair of pink shoes.
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