BRADY BUNCH star BARRY WILLIAMS in lurid smackdown with baby mama “spousal equivalent” – hurling invectives, shocking claims and WORSE.

Here’s  the story, of a single lady, who’s bringing up her lovely daughter all alone …

But for the baby mama battling the oldest of “The Brady Bunch” kids in court, there may not be a happy sitcom ending, The National ENQUIRER has exclusively learned.

Aging child star Barry Williams, 60, is locked in a bitter legal fight with Elizabeth Kennedy, 36, over their two-year-old daughter, Samantha – and both are hurling eye-popping charges of alcohol abuse, drug use and child 

Elizabeth claims she was Barry’s “spousal equivalent” for seven years, but has single-handedly raised Samantha, court documents exclusively obtained by The ENQUIRER have revealed.

The little girl has bounced in and out of the hospital since she was born three months premature, weighing just two pounds, Elizabeth said, and she has accused Barry – who played Greg on the hit ABC sitcom – of “physically and emotionally abandoning their daughter.”

Elizabeth is demanding full custody as a result of Barry’s “history of alcohol abuse,” and wants monthly child support of $3,423 based on the over $13 million estate she claims he’s got tucked away.

She’s also demanded that the court grant Barry only supervised access to Samantha, because he “is often too preoccupied with other distractions to be able to give … the appropriate attention and care she needs.”

Barry has come out firing with both barrels, claiming Elizabeth was never his spouse, but a kept woman who tried to trap him by getting pregnant after he refused to marry her and she refused to get a job!

“She was nothing more than a sexual companion who I treated very well, including paying $23K for dental work because of her neglect of her teeth,” he wrote in the scathing court documents.

“I also paid $11K for her to attend Paul Mitchell Beauty School so she could be self-supporting, all to no 

Barry also accused Elizabeth of being in cahoots with his ex-wife, and admitted to paying $1,400 a month in child support for their son.

But he claimed he’s worth only about $4 million, and denied Elizabeth’s allegations that he abused alcohol.

“I categorically deny each and every insult upon me as being the rants of a scorned woman,” he wrote.

“I do not and have not abused alcohol or any drugs, legal or illegal.”

A hearing on the case is set for Aug. 14 in California’s Orange County, and in a final explosive jab, Barry blamed Elizabeth’s drug abuse for causing their daughter’s premature birth.

He wrote: “In fact it is the [mother’s] heavy use of marijuana and 
cigarettes throughout the years preceding her 2011 pregnancy that likely contributed to … the fact our daughter was born prematurely.”