Goldie Hawn was a cocaine-using bed-hopper who spent more time working on her career than being a mother to her actress-daughter Kate Hudson. Those are just some of the shocking charges fired off by the star’s ex-husband in a blockbuster new book to be published this fall.

Bill Hudson – a member of the ’70s pop band The Hudson Brothers – paints a dark, unflattering picture of the “Private Benjamin” and “Rowan & Martin’s Laugh-In” star, according to a publishing source familiar with the contents of “So You Are A Star.”

Even before writing the scathing book, Hudson has long been bit­ter over the fact Kate con­siders Goldie’s longtime part­ner Kurt Russell her dad instead of him.

In the book, Bill reveals that he met Goldie on a plane trip from New York to Los Angeles – and on their second date back in 1975, they went to see the Rolling Stones in Los Angeles. It was there, Bill claims, that he first saw Goldie use drugs, including cocaine and marijuana.

Bill writes: “A joint got passed to Goldie, and she took a giant toke. By around song three of the set, Goldie was dancing with people in the aisles. A huge plate of cocaine came by and she took a huge snort.”

The two be­came lovers, and Bill details how she almost derailed their romance by ad­mitting she was also in a rela­tionship. Bill says Goldie told him she loved him but believed in “open” relationships.

Despite the turmoil between them, they married in 1976.

The couple had two children: Oliver in 1976 and Kate in 1979 – but the kids  soon took a back seat .

“Her priorities shifted when she started filming ‘Foul Play’ with Chevy Chase, and our kids were left as No. 2 priority,” Hudson wrote. “I couldn’t believe I was seeing that.”

All the details are in the new ENQUIRER – on sale NOW!