Lindsay Lohan -- Oprah Scared the Crap Out of Her

Lindsay Lohan will get to keep her huge paycheck from Oprah Winfrey ... but only after an intense showdown between O and LiLo ... TMZ has learned.

We've confirmed ... Lindsay was a disaster at the beginning of the project -- at times just being a no-show -- which doesn't work in Oprah's world. We're told Oprah went to Dina's house on Long Island for a showdown with Lindsay. She told Lindsay either clean up her act or the project is over and Lindsay would not get her $2 million paycheck.

Our sources say Lindsay had a bunch of excuses ... she was spending time trying to find an apartment in NYC, she had other projects she was trying to finish, there were "miscommunications" between her people and the folks at OWN, yada yada.

Oprah made the ultimatum clear and Lindsay got the message.

We're told Lindsay is now cooperating and things have been running okay for nearly a month, but Oprah is still watching Lindsay like a hawk.