OPRAH WINFREY and FIRST LADY MICHELLE OBAMA have clashed repeatedly behind the scenes, according to a blockbuster new book!

Oprah and Michelle have clashed repeatedly behind the scenes, an unseen war that has dramatically played out BEFORE and DURING Barack Obama's presidency, according to a new book filled with blockbuster allegations.

"The Amateur: Barack Obama in the White House", written by Edward Klein, charges that a highly distrustful Michelle accused Oprah of wanting to use the White House to pump up her TV ratings and that both women have traded insults about each other with close associates.

Michelle allegedly insulted Oprah's weight at one point, with Oprah claiming that the First Lady "hates fat people."

When Obama gained Oprah's endorsement for the 2008 presidential election, the talk show queen enjoyed a close relationship with both the future president and his wife. But once the election was over, the author claims that Michelle and her staff rudely pushed Oprah aside, while the president remained close to the talk show titan, RadarOnline.com reported.

In one particularly outrageous allegation, Klein writes that Michelle turned down Oprah's invitation to appear on her TV show to discuss childhood obesity, one of many causes adopted by the First Lady.

RadrOnline.com reported The book claims Oprah then raged: “Michelle hates fat people and doesn’t want me waddling around the White House!”

Klein, a regular contributor to Vanity Fair, follows that allegation with another bombshell, writing that Michelle told her staff: “Oprah, with her yo-yo dieting and huge girth, is a terrible role model. Kids will look at Oprah, who’s rich and famous and huge, and figure it’s OK to be fat.”

Klein's book contends that the President has remained close to Oprah but that Michelle started pushing her away shortly after the 2008 election, refusing to return calls and instead letting aides deal with Oprah.

The book also contends that two of Michelle's advisers were unhappy with Oprah's influence and that the talk show host was so comfortable with her access to the President, she had a plan to redecorate the Lincoln bedroom!

The author quotes sources close to Oprah claiming that Michelle is "very jealous" and lacks trust in her husband.

These sources also contend that the president phones Oprah late at night and asks for advice to improve his popularity, a move that does not sit well with the First Lady.

"Michelle thinks he should turn to her, not Oprah, for that kind of advice," the book quotes an anonymous source.