Fast Food Boss
... for Friend's Video
Charlie played the role in "Steak and Mashed Potatoes" for free -- as a favor to his pals Simon Rex and Jack Splash -- who recorded the song as the rap duo Chain Swangaz. 2 Live Crew member Brother Marquis was also featured on the track and in the video.
We're told it was shot about a year ago when it was still smooth sailing on "Two and a Half Men" -- and ironically ... in the video Charlie plays the kinda hard-ass boss he accused Chuck Lorre of being.
The song is ... umm ... enjoy Charlie's performance.