Jermaine Jones -- the 6'8" "American Idol" contestant dubbed "The Gentle Giant" -- had an unwanted caller last night ... his dad.
Jones and his mom had it rough after his father abandoned him 10 years ago. But it's amazing what a little fame and potential earning power can do to a fractured relationship.
Last night ... Jones' dad called and tried to make nice. Sources tell us ... the dad told Jermaine, "Hi, I'm in Los Angeles. Why are you telling everyone you haven't got a dad?" We're told the 25-year-old contestant was "extremely upset" by the call.
Jermaine told a friend, "He's a lovely man but a lousy father."