Frankie Valli Divorce -- 'Jersey Boys' Could Cost Him Pretty Penny in Divorce

Frankie Valli -- the lead singer of "The Four Seasons" and brainchild behind the musical "Jersey Boys" -- is learning a hard lesson about marrying younger women, because his ex is trying to take him to the cleaners.

Randy Valli -- who was married to Frankie for 27 years -- has filed legal docs, asking the divorce judge for attorney's fees, but what's really interesting is how much money he makes -- and she already gets.

According to legal docs, Frankie is raking in more than $515,000 per month -- presumably a big chunk is from "Jersey Boys."

But 51-year-old Randy is already getting a big piece of the 77-year-old Frankie. For starters, she gets $30,000 a month -- $5 grand in spousal support, and $25,000 grand a month in royalties from "Jersey Boys."

And this is interesting ... even though she's pulling in more than a third of a million bucks a year, the docs say she's getting $810 a month in public assistance. It looks like that money is for a portion of his SSI because she's taking care of their minor children.