50 Cent has SERIOUSLY upgraded his personal security team ... 'cause one of the guys watching his back is UFC Hall of Famer (and ex-WWE superstar) Ken Shamrock!!!!
49-year-old Shamrock was spotted on the rapper's personal protection detail at the CES convection in Las Vegas yesterday ... and afterward, Ken confirmed he's now working for a company that does private security for several "high-end clients," including Fiddy.
After the convention, Ken tweeted that it was a "pleasure" working for 50 ... and said the rapper is, "By far one of the classiest gents I have ever worked with."
As for Ken's fighting career -- he may not have given up on the ring entirely ... just last month, he appeared in a wrestling event in Costa Rica.
But for now, don't screw with Mr. Cent ... or you might end up in a nasty ankle lock.