Joe Jackson, Quincy Jones Knows Better than to Say Michael Stole Billie Jean

Joe Jackson was quick on the trigger when our photog asked about Quincy Jones' claim Michael stole the hook from "Billie Jean."

We got the elder Jackson Saturday at Toscanova in Calabasas, and Joe seemed pissed Q threw shade on his late son. Quincy says MJ stole the hook from the Donna Summer's song, "State of Independence."

Truth be told ... there's no doubt Michael lifted the hook. Quincy was the producer of both "State of Independence" and "Billie Jean," and Michael actually sang on Summer's song in question.

As we first reported, when you slow "State of Independence" down, the hook on "Billy Jean" is almost identical.