WWW- ‘Insider’ host Pat O’Brien entered rehab as a voice on a booty-call tape was said to be his. What’s the inside story on “Insider” host Pat O’Brien’s decision to enter rehab Sunday?

Hollywood sources suggest the timing was to defuse the release of several sexually explicit voice-mail messages, available on the Internet yesterday, soliciting sex from an unidentified woman.

“Let’s just [bleeping] have sex and fun and drugs and go crazy,” says a male voice.

Yesterday reps for “The Insider” would not comment on widespread attribution of the voice to O’Brien.

The tape describes in graphic detail just how “badly” the caller wants various activities that involve, gosh, all parts of the woman’s body.

“I’m so into you, Betsy is so f–ing jealous,” the voice claims in one message. “I know you want me, but you have to be with Betsy, too.”

“The Insider” host has one child with his wife, Linda.

Sadly, by the final message, Betsy seems to have pulled out of the threesome.

Says the caller: “Get another woman up, hire a hooker, let’s get crazy, get some coke and if you get this message, if you agree with this, just look at me and say yes.”