9:55 AM PT -- Sarah Huckabee Sanders has just responded on behalf of the White House, calling Omarosa a "disgruntled former White House employee" who is "trying to profit off these false attacks."

8:42 AM PT -- George just released a statement, saying, "The allegation is not credible, and indeed is ridiculous, particularly in light of the timing of her departure from the White House -- December 12, 2017. It's absurd all around."

Although Conway does not specify why the timing is significant, it appears the majority of his public criticism of 45 came well after Omarosa's departure.

Omarosa says she has dirt on Donald Trump ... and it's racial.

Omarosa -- who briefly worked for the Trump Administration -- claims in her upcoming book, "Unhinged," she witnessed Trump use racial epithets in talking about the husband of White House Counselor Kellyanne Conway.

According to Omarosa, Trump referred to George Conway, who is half Filipino, as a "Flip" and a "Goo-goo."

Omarosa also says there are tapes that exist in which Trump used the n-word on the set of the TV show, "Celebrity Apprentice."

The Guardian first reported her claims.