R. Kelly Ain't Cheap, Even for Michael Jackson

Michael Jackson's estate has a new creditor's claim -- thanks to one R. Kelly.

Michael sang Kelly's song "Ignition" in his car as part of the TV show, "Michael Jackson's Private Home Movies" -- but never paid for it.

Universal Music Publishing Group, which owns the rights to the song, wants Jackson's estate to pay $3,000. Universal attached a contract to the creditor's claim, showing the fee in black and white.

Will estate lawyer Howard Weitzman pay the claim or pee on it?

Stay tuned...