Rochelle gave birth to a baby girl called Valentina Raine.
Marvin announced the news on Twitter where he referred to his new daughter as an “incredible blessing”.
He tweeted: “Couldn't be a happier or prouder man, what another incredible blessing! My beautiful wife gave birth to our 2nd girl Valentina Raine Humes x.”
Couldn't be a happier or prouder man, what another incredible blessing! My beautiful wife gave birth to our 2nd girl Valentina Raine Humes x pic.twitter.com/xxIwQhLy1Z— Marvin Humes (@MarvinHumes) March 10, 2017
He posted the tweet alongside a picture of his wife cradling their new addition in a hospital bed.
The celebrity couple are already parents to three-year-old daughter Alaia-May who was born in May 2013.
They announced the news that they were expecting their second child in November when Rochelle posted a black and white picture of her baby bump.
She captioned the image: “Ten tiny fingers, ten tiny toes, but who are you? Nobody knows...”
Former JLS star Marvin also posted a number of snaps of his wife posing in grey Calvin Klein underwear, writing: “Absolutely delighted to announce that we're extending our family! Rochelle and I are over the moon! Baby Humes no2 is on the way!!!”
Rochelle recently revealed that her daughter was very keen to have a brother or sister, telling The Sun: “I’m feeling it from Alaia, for sure! She’s already quizzing me and saying that her friends all have brothers or sisters.”