Toddler swearing

Noone in my house swears, but recently my toddler has started to randomly swear, in the right context too.

I was just doing a workout in the living room while baby sleeps and his playfighting something imaginary with a plastic sword (his 3 years old, almost 4), sits down, looks at the TV and the kitty catastrophe crew (paw patrol) did something naughty again, and my son goes "what the fuck?!?". This isn't the first time his used the word "fuck", there's been what the fuck, fuck sake and fucking hell, I don't get angry when he says it and tell him to stop saying that word because it's naughty. Today after that incident I decided to ask where his even learnt that from, he asked "learned what?" I go "what the fuck?" and he went "stop saying that, it's naughty" 🤦🏼‍♀️🤦🏼‍♀️🤦🏼‍♀️

He goes to pre school, maybe learnt it from a kid in there? 🤷🏼‍♀️