The former Spice Girl took to social media to announce the arrival of her second child with her husband Christian Horner, reported AceShowbiz.
"Christian and I are delighted to announce our baby boy was born this morning weighing 7lbs 8oz," tweeted Geri.
Revealing her newborn son's name on Instagram, the singer also posted the first photograph and wrote, "Montague George Hector Horner arrived this morning, a beautiful little brother for Bluebell and Olivia #amazing-day #grateful #monty."
The couple already has a daughter, Bluebell who was born in May 20016.