Shannon Briggs -- Inking Deal to Fight Klitschko ... 'It's Going Down!'

LET'S GO CHAMP!!!

2-time heavyweight champ Shannon Briggs just told "TMZ Sports" hes' FINALLY getting his fight with Wladimir Klitschko ... after roughly TWO YEARS of chasing the guy down around the globe!

Briggs joined the guys on "TMZ Sports" (airs Tuesday at 9PM PT on FS1) -- and said he's been in negotiations with Wlad for the past couple of weeks ... and they're finally bringing it in for a landing.

Briggs has literally traveled the globe trying to goad Klitschko into a fight -- picking fights with the guy on land, on sea ... and in the middle of restaurants.

So, how did he finally get Wlad to meet him in the ring?

Make sure to watch "TMZ Sports" tonight for the whole story.