Geri Horner has given birth to a baby boy named Montague George Hector Horner.
The 44-year-old former Spice Girl announced the news on Twitter on Saturday morning, the Daily Mail reports.
This is Geri and 43-year-old husband Christian Horner's first child together.
"Christian and I are delighted to announce our baby boy was born this morning weighing 7lbs 8oz", she tweeted.
The delighted singer - who is also mum to 10-year-old daughter Bluebell, added a baby and bottle emoji to her tweet.
Christian and I are delighted to announce our baby boy was born this morning weighing 7lbs 8oz— Geri Horner (@GeriHalliwell) January 21, 2017
She then took to Instagram to share a snap of her holding her son's tiny foot, announcing his name with: "Montague George Hector Horner arrived this morning, a beautiful little brother for Bluebell and Olivia #amazing-day #grateful #monty".
The birth coincides with Geri's ex bandmate and gal pal Emma Bunton's birthday, with Emma taking to Twitter to congratulate her with the hashtag 'birthdaytwins'.
Geri's first Saturday tweet was a birthday message to Emma. She shared a throwback of the duo in their Spice Girl days and a heart emoji before sharing her baby news.
"Amazing news, so happy! #Birthdaytwins #Birthdaymade love you all. Xxx", Emma replied happily, and fellow Spice Girl Melanie Chisholm also tweeted her congratulations.
Woo hoo!!!!! Congratulations! So exciting! @GeriHalliwell— Melanie C (@MelanieCmusic) January 21, 2017
And the singer's fans were delighted with the news, with her tweet garnering almost 1000 likes in just twenty-five minutes.
The news comes shortly after it was reported Geri had dropped out of the Spice Girls reunion 'GEM'- where she was due to unite with Mel B and Emma, to focus on her family.
A source told The Sun before her birth: "Geri's priorities have changed. Her baby is due later this year and rather than force a reunion, she's needs to concentrate on more personal matters.
"Getting all the girls in the studio at the same time proved a tough task. What they needed was one main boss-style figure to pull the strings otherwise they would be constantly in limbo."