The Girls Aloud singer, 29, uploaded the pretty photo to Instagram overnight, simply adding the caption: "Awesome."
In the snap, former American football player Jason can be seen cradling little Anaíya while walking along the beach in sunny California.
Fans were quick to leave their compliments on the photo – and Nadine's gorgeous little family – with comments including, "Aww, that is adorable" and, "This is beyond cute! Looks amazing!"
Northern Irish-born Nadine gave birth to Anaíya, her first child, in February, but has largely kept her away from the spotlight. That hasn't stopped her frequently gushing on social media, however, about how much she loves being a mum!
Nadine, who was the first member of Girls Aloud to give birth, currently lives in LA with partner Jason, 36. They began dating in 2008 and became engaged, but briefly split a few years later.
They keep their romance so private that when Nadine announced her pregnancy last year, no one even knew Jason was the dad!
At the time, she said: ""When I said I was pregnant I thought, 'Why's everyone wondering who it is?' Then I remembered, 'Oh yes, that's right. I do stuff on TV and people are confused. So this clears it up!'"
Meanwhile, Nadine recently encouraged her Girls Aloud bandmate Cheryl Fernandez-Versini to "join the baby club" after Cheryl announced her shock marriage to boyfriend Jean-Bernard.
Got an iPad or iPhone? Reveal Mag is specially designed to fit!
Stars who welcomed babies in 2014: