The model welcomed a healthy baby boy on Easter Monday and named him Otto James.
She and her husband Spencer Matthews are also parents to three-year-old Theodore and one-year-old Gigi.
Taking to Instagram on Tuesday, the Dubliner shared a photo of little Otto having a snooze, which she captioned “Sweet dreams.”
Vogue then got a message in response to the snap from a follower who gushed that he was the “image of Spencer” and a “beautiful baby” but asked if he was “a little bit jaundiced.”
The mum-of-three was amused by her fan’s concern and shared the message on her Instagram Stories.
She joked that the tot had been using her latest tanning product – a Hyaluronic Acid serum that promises to leave users with “a natural looking, bronzed glow” on their face – to get his tanned complexion.
“Otto is not jaundiced,” she clarified.
“He’s just mad for the new [Bare By Vogue] face serum.”
Vogue, who lives in London with her family, also revealed that she had taken Otto over to the Emerald Isle for the first time since he was born last month.
She shared some snaps from along the Howth cliff walk with her newborn strapped to her chest as she hiked in the sun with her pal.
Speaking to Hello! Magazine recently, Vogue shared how Theodore and Gigi have been adjusting to life with their new baby brother.
“We feel very fortunate and really blessed - we couldn't ask for better kids.
“It's always been our intention to have a big family and we are very lucky that we have been able to do that.”
She added: “Otto slotted in straight away. The kids love him and we are obsessed with him. Theodore and Gigi love playing with each other and I think that Otto’s going to be another little member of their gang. It's really lovely to see.”