Chris Brown Claims Michael Jackson AMAs Tribute Canceled Inexplicably

Chris Brown says he was supposed to put on a big tribute to Michael Jackson during the AMAs this weekend -- but claims honchos pulled the plug last minute out of nowhere.

The singer posted a lengthy video Saturday that shows him in a dance rehearsal with a group of people ... and he's putting on some serious MJ-inspired moves to a few classic hits, which Chris says would've been part of a showstopping number during Sunday's broadcast.