Russell Brand Billboard Vandalized ... Hilariously

Russell Brand's new TV show isn't getting much support from the graffiti community.

Some clever vandal -- who clearly isn't a fan of Russell's new late night talk show "Brand X" -- decided to tag a billboard for the show on Sunset Blvd. with a special spray-painted diss ... involving Russell's estranged wife Katy Perry.

It's pretty funny ... and it pretty much speaks for itself ... so we gotta ask ...