Sam, who won The X Factor in December, said the baby wasn't planned but that she is looking forward to being a mum again.
The star has even revealed that she found out about her pregnancy while in a supermarket with her husband Craig!
Sam, who is 10 weeks gone, told The Sun how she took a test in Asda's customer toilets: "I went in and did it while he was getting all the food," she revealed.
"I came out and went, 'Yep, I'm pregnant'. It wasn't planned."
Sam, 36, and 40-year-old Craig are already parents to son Tommy and daughter Brooke. Earlier this year, Sam told Reveal how winning The X Factor had brought her and hubby Craig closer together.
The singer had planned to undertake a solo UK tour beginning in October, however it will now be postponed until January 2015.
Sam, who previously worked as a prison guard, won The X Factor after going head-to-head with hopefuls Nicholas McDonald and Luke Friend in the final.
After her win, Sam released her debut single 'Skyscraper' - a cover of the Demi Lovato hit - and secured the Christmas No 1.
Not only did she bag a £1 million recording contract with Simon Cowell's record label Syco, Sam also supported none other than Beyoncé on her 'Mrs Carter World Tour'.
However, although she was reportedly due to take part in 10 UK shows last month, it was cut to one due to her commitments with 'The X Factor Live Tour'.
Last month, Sam unveiled the cover artwork for her forthcoming debut album 'The Power Of Love'.
Given that Simon has recently become a father for the first time to baby Eric - and is loving it - we imagine he'll be delighted for Sam.
Celebrities who have announced pregnancies in 2014:
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