MEL GIBSON may be ready to head down the aisle with GF Nadia Lanfranconi, but the sexy singer/ songwriter is being warned to run the other way!

“Anyone who marries Mel Gibson, with his despicable record of boozing, cheating and bigoted ranting, would have to be crazy,” a source told The ENQUIRER. “That would truly be a match made in hell!”

Gibson has been dating Nadia since 2012 and recently showed her off at a charity event in West Hollywood. But Mel is still reeling from his bitter breakup with Oksana Grigorieva, mother of his 4-year-old daughter, Lucia. The illicit romance with Oksana shattered his 31-year marriage to now-ex-wife Robyn – and cost Mel a staggering $400 million in a divorce settlement.

Oksana filed for a restraining order, claiming that her hot-headed baby daddy gave her a concussion and knocked out her teeth.

Mel’s been giving Oksana $20,000 a month for child support while they share custody of Lucia, but now he’s causing her another nightmare by threatening to seek FULL custody of the girl.

Nadia will also need to deal with her 58-year-old beau’s longstand­ing drinking problems and bigoted behavior. He’s faced multiple DUI arrests and been caught making hateful anti-gay and anti-Semitic statements.

But sources say that Nadia has been a calming influence on the “Mad Max” star, and she even has the seal of approval from Mel’s ex Robyn and their seven kids.

Still, it appears that Nadia may be better for Mel than he is for her. “Mel Gibson has a reputation as an alcoholic, violent, out-of-control, raging bigot,” the source added. “Any woman who marries him is in for big trouble.”