He also posted a solo portrait of the adorable animal chewing on a toy in a grassy field, captioned:
"Whatcha looking at."
Mum of the brood Victoria shared her love for the new pet, too, posting an image of eldest son Brooklyn holding little Sage, with the pooch's cute face pointed towards the camera to give fans and followers a front-on view.
"New family member Sage Beckham x," she wrote.
It's clear the whole famous family is totally smitten with sweet little Sage, who appears to be a cocker spaniel, like the family's two other dogs, Fig and Olive.
"New member to the family ❤️," Brooklyn wrote.
Fig and Olive were involved in the family's Christmas celebrations, too, of course.
The pair of pooches were decked out in festive red-and-white doggy attire and looked like they were enjoying the holiday fun, with Brooklyn sharing videos of them racing around the property and playing with their new puppy pal.
Just days before, proud papa David shared an adorable message from his daughter Harper.
Sharing the video to Instagram, the footballer wrote: "I mean come on this is ridiculously cute & Harper wanted to wish everyone a very Merry Christmas 🎄♥️ #ASL."
Fans also agreed that the message was heart-melting.
"I know a little sign language because I have a friend who is deaf. Harper did a great job!!
"She will make someone very happy when she comes across someone who is deaf."
Harper was also baptised just days before Christmas, with actress Eva Longoria named as one of her godparents.
“Proudest of days today watching Harper and Cruz being baptised in front of our friends and family 🙏🏻 So much to be grateful for x,” Victoria captioned a photo of her children on Instagram.