First lady Melania Trump speaks on the second day of the Republican National Convention from the Rose Garden of the White House, Tuesday, Aug. 25, 2020, in Washington.

President Donald Trump and first lady Melania Trump arrive on South Lawn of the White House on the fourth day of the Republican National Convention, Thursday, Aug. 27, 2020, in Washington.

WASHINGTON (AP) — A former friend and adviser of Melania Trump says it was “the worst mistake of my life” to work for President Donald Trump and his family, lashing out at the first lady for not defending her over questions about costs for the presidential inauguration she helped produce.

Stephanie Winston Wolkoff was an unpaid White House adviser to the first lady until February 2018, when her contract was terminated as questions about inaugural spending arose.

“When it really counted, Melania wasn’t there for me,” Wolkoff writes in “Melania and Me: The Rise and Fall of My Friendship with the First Lady,” to be published Tuesday.

“She wasn’t really my friend. In fact, I wish I had never met her,” Wolkoff says about the first lady, a former fashion model. Wolkoff, a New York-based event planner, said the pair first met in 2003 in the hallways of Vogue magazine, where Wolkoff worked.

Stephanie Grisham, a spokesperson for Mrs. Trump, blasted the book in an emailed statement as “full of mistruths and paranoia” based on an “imagined need for revenge.”

Wolkoff also writes about frostiness in the relationship between the first lady and the president’s eldest daughter, Ivanka Trump. She said she and the first lady both once “bellied over with laughter” after Mrs. Trump referred to Ivanka Trump — long seen as her father’s favorite child — as “Princess.”

Wolkoff also detailed how they launched “Operation Block Ivanka” to keep her from being too prominently featured in inauguration day photographs of her father being sworn in to office.