John Stamos' wife says they want to expand their brood ''as soon as'' possible.

The 'Fuller House' actor and his spouse Caitlin McHugh welcomed a son called Billy into the world last month, and they are already thinking about giving their little boy a sibling because they don't want to have a ''spoiled'' only child.

Asked if they want more kids, Caitlin told 'Entertainment Tonight': ''As soon as I can!

''Right now, Billy is extremely spoiled and we need to share the love, he's gotta share some of those toys and all the things that have been given to him. He needs [siblings] to keep him grounded. If he's the only one, he'll get way too much love because there hasn't been a child on either side of our family in quite some time.''

Caitlin gushed about how ''naturally'' the actor took to parenting, especially as he had always said he would never change a diaper.

She said: ''He used to say he's not going to change any diapers... and he's changed so many diapers! He totally doesn't mind it. It's beautiful seeing [John] with Billy. It all feels so right. It feels like this is the way it should've always been.

''He comes so naturally to fatherhood and I love watching it. I stare at the both of them all the time beaming. [John is] 100 per cent full-on active and fantastic ... He's perfect, he's a perfect father. I can't wait to give him more [kids].''

John - who is best known for playing Uncle Jesse in 'Full House' and 'Fuller House' - revealed the couple's arrival on Instagram by sharing a black and white photo of the baby resting on his chest and clutching his finger.

He captioned the image: ''From now on, the best part of me will always be my wife and my son. Welcome Billy Stamos (named after my father) #NotJustanUncleAnymore #Overjoyed (sic)''