Axl Jack Duhamel, who is three weeks old, appears in the super-cute picture alongside the message: "hello world!!!! #daddyandmommymademedothis #whatsahashtag."
Proud mum Fergie posted the snap yesterday (21 Sept) and it's only the third picture that she and husband Josh have shared of the little babe.
Black Eyed Peas singer Fergie, 38, and her Hollywood actor husband Josh, 40, became proud parents to their first child, Axl, on Thursday, 29 August. He weighed 7lbs 10oz.
Two weeks later, they introduced him to the world when they shared the first pictures of him from his early days in hospital.
Fergie and Josh announced the pregnancy back in February, with Josh then confirming in July that they were expecting a baby boy.
The couple have been keeping a low profile since becoming parents. Fergie's most recent public appearance was on 20 August, when she supported Josh at a screening of his new movie Scenic Route in Los Angeles.
Rocking leather and studs, the 'London Bridge' singer jokingly referred to herself as "rocker mummy".
Do you go gaga at the sight of little babe Axl? Tell us what you think below!
Watch the video for Fergie's single 'Fergalicious':