'Pants on the Ground' -- Las Vegas Bound

"General" Larry Platt is finally cashing in on his "Pants on the Ground" phenomenon -- because "American Idol's" favorite senior citizen is now getting paid to play in Las Vegas.

Platt is scheduled to perform his semi-hit at JET nightclub at the Mirage Hotel on Friday.

Sources at the hotel tell TMZ Platt is being flown from Atlanta first class ... and will get pampered with free food, lodging, several thousand dollars and, last but not least, a steak dinner!

TMZ spoke to Platt's manager, who said this is just one of many shows Mr. Pants has booked recently ... which means the old man is finally getting the money his musical genius deserves.