Jonah Hill, Bradley Cooper Fanboy Out Over Dave Chappelle

Dave Chappelle is tuning up his stand-up act with some cool pop-up shows in small venues, and bringing out big name fans ... including Jonah Hill and Bradley Cooper.

We got all 3 guys leaving the Blind Barber in L.A. Monday night after Dave finished his set, and the "War Dogs" co-stars looked and sounded thrilled with what they'd just seen from the comedian.

Check out Jonah and Brad's exchange with Dave -- based on their reaction, Chappelle's upcoming Netflix specials are gonna KILL.