Tekashi69 is getting serious about protecting himself -- he's hired 2 dudes who've proved themselves guarding boxing champ Floyd Mayweather.
Sources close to the Brooklyn rapper tell TMZ ... Tekashi brought on a couple of dudes from Floyd's old security detail -- both of whom are simply known as "The Great Wall." They have actual names though -- Big Church (the biggest dude in the back here) and Big Adam (the slightly shorter dude in the leather jacket up front).
We're told 6ix9ine and his team decided they needed to beef up his security presence after a fan was able to rush him onstage, during a show in Moscow.