Melissa Gilbert
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 MELISSA GILBERT’s goody-goody image is about to take a major hit!

As her divorce from Bruce Boxleitner draws near, book agents are clamoring for him to spill Melissa’s dirty secrets in a shocking Hollywood tell-all, a publishing insider tells The ENQUIRER.

“They’re champing at the bit for the REAL story of Melissa’s life,” revealed the insider, who says the actress’ own 2009 memoir, “Prairie Tale,” is nothing more than a “sugar-coated, G-rated” version of the truth.

“Melissa’s had a long, rocky battle with booze, complete with blackouts and violent outbursts,” noted the source.

Her out-of-control years on alcohol and cocaine are just a giant blur – and Bruce knows ALL the details.

“It’s a far raunchier storythan Melissa would ever tell – but that’s what would make it a best-seller. That’s what publishers want Bruce to write.”

At 17, the former “Little House on the Prairie” star began dating Rob Lowe and became engaged. But he dumped her after learning she was pregnant. Tragi­cally, she miscarried.

She was also allegedly dating Tom Cruise and Scott Baio while still with Lowe.

Back then, “booze was the only constant in Melissa’s life,” said the source.

Se drank throughout her first marriage to actor Bo Brinkman, and by the time she married Bruce in 1995, she was downing two bottles of wine a night, the source maintained.

“Bruce witnessed a living hell. And THAT’s the story publishers want.”

All the details are in THE ENQUIRER – still on sale!