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.

The songs featured include "Beat It," "Billie Jean," "Wanna Be Starting Something" and "Thriller." Presumably, this is in line with the 40th anniversary of Mike's best-selling album.

Chris's original caption reads, "U SERIOUS?" He followed up in a later comment, writing ... "WOULDVE been the ama performance but they cancelled me for reasons unknown." IG users are mostly in support of Chris, openly asking why they scrapped it if it was this good.

Of course, there's speculation as to why CB's performance may have been nixed. Frankly, he's controversial ... even all these years later. Michael himself is obviously also polarizing ... especially in more recent years with the allegations highlighted in the documentary "Leaving Neverland."

Still, Chris's tribute would've been a nice full-circle moment -- the guy has famously done MJ tributes in the past, like in 2010 when he did a big one at the BET Awards ... a year after Michael had died.

There's also the nonstop comparisons made between himself and the King of Pop. Akon recently brought it up again, saying Chris could've been as great if he had a cleaner crew.