Ivanka and Melania Trump
Ivanka Trump and Melania Trump watch as President Donald Trump speaks in the Oval Office of the White House, in Washington, D.C., Feb. 28, 2017. REUTERS/Joshua Roberts

Amid speculations that Melania Trump and step-daughter Ivanka Trump have frosty relationship, the latter — in her new book “Women Who Work” — praised the first lady and thanked her for the "support and friendship."

"Melania, you are an unbelievable mother with a heart of gold. You give generously of your time and attention and I appreciate your support and friendship," Ivanka wrote, according to CNN reporter Betsy Klein’s tweet that had a photo of the book’s excerpts.

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This isn’t the first time President Donald Trump’s eldest daughter praised the former model. Ivanka called Melania an "incredible stepmom" on the latter’s 47th birthday on April 26.

"Happy birthday to our First Lady (and my incredible step-mom!) Melania Trump," she wrote in post. "A wonderful example of kindness and grace for us all!"

Ivanka’s praises to Melania come after Vanity Fair reported last week, citing sources, at the two have a “frosty” relationship. However, a source close to Ivanka said the relationship between the two is "fine," while Melania’s spokeswoman said: "Ivanka and Mrs. Trump have always shared a close relationship, and that continues today."

Speculations about Ivanka and Melania’s frosty relationship are likely to have cropped after the 35-year-old was mostly seen by her father’s side throughout his presidential campaign. She also got an unpaid role in the White House. Melania, meanwhile, stayed back in New York City with her 11-year-old son Barron to complete his academic year. Recent reports said that she would be moving into the White House in June, when Barron will complete his school year in New York before possible transitioning to the Sidwell Friends School, which is the most common school used by president’s children during their time in office.

Melania and Trump also were not present at Ivanka’s spring break trip to Aspen, Colorado, in March. However, a White House representative maintained that Melania and Ivanka share an amicable and close bond.

“Melania is an unbelievable mother. It’s pretty uncommon for wives of candidates to not be on the campaign trail every day. And she made a decision I totally respect, which is that she has a young son, he needs stability, he needs routine,” Ivanka told People in July 2016 of Melania's decision to fly under the radar. “My father’s traveling so frequently, and she is an unbelievably consistent, loving and reliable figure in Barron’s life.”

Ivanka also commended the first lady’s work with charitable organizations and said: "Melania is very smart, she’s very warm, she’s got an incredible heart."