Before Ric Flair doles out one last ass whoopin', the WWE legend's gonna take a few (verbal) jabs from Mike Tyson -- 'cause TMZ Sports has learned Iron Mike will be one of the celebs roasting Nature Boy this summer!
We're told 55-year-old Tyson has signed on to be part of the roast of 73-year-old Flair ... going down July 29 in Nashville, TN ... in front of over 1,000 fans!
Ric and Mike -- two of the absolute greatest in their respective fields -- aren't just buddies, they're also business partners.