MEG'S WARNING: MELLENCAMP HURTS SO GOOD!

ROCKER John Mellencamp is smitten with well-heeled widow Kristin Kristin Kehrberg — but sources dish his former fiancée Meg Ryan wants to warn the sexy socialite she’s going to get burned! 

“Meg believes John is poison to any woman and will only make Kristin miserable in the end. She’s trying to get the message to her about what she’s in for,” squeals an insider.

“John may pour on the charm in the beginning — but he’s selfish to the bone. Sooner or later he will slide back to his bad habits, like neglecting to call, forgetting birthdays and showing up late — or not at all.”