The baby will be the first for the British singer, formerly known as Geri Halliwell, and her husband, Red Bull Formula One team boss Christian Horner, who she wed last year (15).
The Wannabe hitmaker, 44, is already a mum to 10-year-old daughter Bluebell, from a previous relationship.
"They are absolutely delighted to announce they are expecting their first child together," reads a statement issued by Geri's representative to The Sun. "The couple is overjoyed with the good news and cannot wait to welcome the newest addition to their family.
Geri hinted at her big news in a cryptic post on social media on Monday (10Oct16), when she shared a photo of a handwritten note, which read, "God bless Mother Nature", a line from her 2001 single It's Raining Men. She signed it, "#mamaspice".
The star's baby news comes just months after she reunited with her old bandmates Melanie Brown and Emma Bunton and announced plans to reform as a trio, dubbed GEM. It is not yet known how the new group will launch its pop comeback now Geri is pregnant.