And Coleen Rooney continued to show off her adorable family addition to her 1.3m Twitter followers on Friday.
The mother-of-four, 31, posted the heart-melting black and white snap - taken by photographer Jocelyn Conway - on the micro-blogging site, which saw the tiny tot swaddled in cloth while sound asleep.
The youngster seemed unaware of his photo shoot as he curled up while sweetly laying his head on his hands with the cloth lightly wrapped around him.
Mum-of-five Coleen captioned the heart-melting tweet 'Our Boy.... love the pictures @Photojos'.
Another tweeted: 'What a beautiful photo, gorgeous little boy', while a third commented: 'How gorgeous Colleen you must be so proud of all four of your boys'.
Coleen and Wayne are already doting parents to eight-year-old Kai, Klay, four, and Kit, two.
Coleen originally announced the news of Cass' birth on Twitter by posting a photo of herself and the tot in hospital, captioned: 'So Happy to welcome our Baby Boy .... Cass Mac Rooney into the world weighing a healthy 8lb 10oz. He is beautiful.'
Wayne, 32, and Coleen have gone from strength to strength after recently repairing their nine year marriage, after it was rocked by cheating scandals during the pregnancy.
It was on Facebook, just three months ago, that Coleen was forced to issue a statement about the status of her marriage, saying she 'thought it might have been at an end'.
'I know I would be fine on my own,' she wrote. 'With just me and my children, but I don't want to live like that, I want to try and continue our marriage and live as a family, because that's what I want to do.'I'm not saying everything is fine and forgotten about, but we are as good as can be at this point, I'm not the type of person to put a show on and say we're all loved-up….I'm just real.'
Insisting she is a 'strong person' and doesn't need people to feel sorry for her, Coleen set the record straight once and for all about her marriage.
She continued: 'A few people are probably thinking am stupid for staying in my marriage. I am not stupid, I know my own mind and it's something I want to try and work on.
'Before the headlines start.... No, I’m not taking Wayne back as he's never left.'
- DailyMail