Erin Moran Brawls with Mother-in-Law

Troubled “Happy Days” star Erin Moran got into it with her mother-in-law, again.

The 57-year-old former child star and her husband, Steve Fleischmann, 45, had been living in a trailer with his mother in Indiana, until they were booted out a week ago for excessive partying.

The National Enquirer reports that after living in motels, Moran and Fleischmann asked to move back in, but the 72-year-old woman refused. Then the wayward couple tried to sneak in, but was caught and a brawl ensued between Steve's mom and Moran.

The situation got so tense that the woman threatened to call the police if Erin didn't leave immediately, a source exclusively told the Enquirer.

"She finally did leave, but Steve's mom was right on her heels, chasing her out of the trailer, shouting at Erin as she made her way across the yard to their car," said the eyewitness. For the full story, the new issue of the National Enquirer is on newsstands Thursday.

Meanwhile, Moran's "Happy Days" co-star Henry Winkler talked with Howard Stern on his Sirius morning radio show on Wednesday and said he was "saddened" by Erin's recent troubles. Watch the clip!