After GOING IN on his recently deceased Happy Days co-star, Scott Baio told TMZ this morning he was wrong to insinuate Erin Moran died from drug-related problems.

To recap: During an interview with “The Bernie & Sid Show,” yesterday, Baio said

“I’m OK, a little shocked but not completely shocked that this happened. My thing is, I feel bad because her whole life, she was troubled, could never find what made her happy and content. For me, you do drugs or drink, you’re gonna die. I’m sorry if that’s cold, but God gave you a brain, gave you the will to live and thrive and you gotta take care of yourself.”

The NERVE.

Now, after an avalanche of online hate, he’s walking back his statement, saying he didn’t know about her cancer.

He tells us he went to bed Sunday reading reports she’d possibly died of a heroin overdose, and went into the interview with that in mind. He was upset he’d lost Erin to drugs after she wrestled with substance abuse for years.

However, hours after he went off the air … officials in Indiana announced Erin had likely died from complications of stage 4 cancer. Scott says if he had known, he would’ve kept his mouth shut.

Maybe after your former girlfriend dies, you should think twice before immediately getting on your high horse and talking to the press. Just a thought.