Mario shared the cute picture with fans last night (3 March) and it shows the tot wearing an identical Miami Heat basketball vest to one he owns.
TOWIE star Mario is a big fan of the team, and even visited a game with girlfriend Emma McVey during a trip to Florida in November.
Alongside the picture, Mario pasted one of himself in his matching vest and told his followers: "The nephew knows! I think he wears it better than me!"
Mario's nephew is the son of his sister Giovanna and her McBusted star husband Tom Fletcher.
The couple welcomed him into the world last March and Mario has been nothing short of a hands-on uncle since his birth.
In the autumn, the Italian tailor began dating model Emma and he recently admitted that things were serious between them.
There's also been talk of Mario and Emma moving in together...perhaps they'd like their own little Buzz one day too?!
Need a TOWIE refresher? Here's all that happened last series!