The pop star couple, who welcomed Alaia-Mai into the world in May, invited Niall round for dinner last night (13 August) before treating him to some milk.
Capturing the funny moment on film, Rochelle took a picture of herself holding a full bottle up to Niall's mouth while her hubby Marvin stroked his head.
Sharing the photo on Instagram, The Saturdays star joked: "@MarvinHumes and I doing the night feed ;) @niallofficial." Niall then replied: "Thanks mammy and daddy."
Rochelle, 24, and Marvin, 28, live around the corner from 19-year-old Niall and treat him like a younger brother.
Along with his One Direction bandmates, Niall arrived home in the UK yesterday following a nine-week visit to the US, so he popped round to the couple's house for some good British food...and milk!
Last year, Rochelle explained that Marvin took Niall and his 1D bandmates under his wing when they first made waves in the industry.
She added: "Niall lives close to us so we make him dinner. He talks to us about girls and stuff and I give my input and say, 'You can't go out with her!'"
Check out which other stars have given birth this year in our gallery below:
Copyright: Love & Lust London