Joseph Ducreux (1735-1802) was both sober professional and hilarious goofball, one of my favorite combinations.

https://en.wikipedia.org/wiki/Joseph_Ducreux

So, he was a multi-talented artist who worked under the 'fat boy'* and somehow managed to survive the bloody French Revolution, alongside his colleague David.

* one of Louis XVI's most notorious nicknames

My understanding is that he was meticulously-trained as an artist, and generally-speaking, did thoroughly professional work... until he had his personal time, in which he decided to 'boogie on down with his bad self,' as we once used to say in the States. I think. XD

But wait, there's more! I understand that some of his pics recently turned in to a sort of cottage-industry of memes. Behold:

EDIT: Alright, alright, here's a couple of those decoded. Most are rap-themed, I think?

#2 They see me rollin', they hatin' (Ridin song reference)
#7 STOP, it's hammer-time (MC Hammer song ref)