WASHINGTON (AP) — Melania Trump knew her inaugural gown would be part of history and she had a clear vision for her look, asking the designer for something "modern, sleek, light, unique and unexpected."

The resulting vanilla silk, off-the-shoulder gown is now part of the First Ladies Collection at the Smithsonian Institution. Mrs. Trump officially donated the couture piece Friday at the National Museum of American History and it has been added to the popular exhibit that features dresses worn by Jacqueline Kennedy, Laura Bush and Michelle Obama and others.

Calling it a "daunting task" to select a dress that will be part of history, Mrs. Trump said "it is now my hope that this piece is one of the many great beginnings to our family's history here in Washington, D.C."

The gown, designed by Herve Pierre in collaboration with Mrs. Trump, featured a slit skirt, ruffled accent trim from the neckline to the hem and a claret ribbon around the waist. The first lady wore it as she accompanied President Donald Trump to celebratory balls on Jan. 20.

Mrs. Trump said after her husband was elected, the family was so busy with the transition that "to be honest what I would wear to the inaugural ball was the last thing on my mind." She said Pierre, who attended the event and also serves as a stylist, had just two weeks to create the gown.

But she added that he "exceeded my expectations."

Pierre, the former creative director of Carolina Herrera, said it was a fast process, but that "a good conversation, a good collaboration leads to something very good."

Mrs. Trump, who officially moved to Washington in June, has been growing more comfortable in her first lady role of late, making a solo trip to Canada to cheer Americans participating in an athletic competition for wounded service members and veterans and visiting a West Virginia care center for babies born dependent on opioids.

A former model, Mrs. Trump has been closely watched for her fashion choices. During a two-day visit to Paris over the summer, she wowed the French in a flame-red skirt suit by Parisian fashion house Christian Dior. The first lady and Pierre picked it to celebrate Dior's 70th anniversary this year.

Pierre said the two are working on her looks for an upcoming trip to Asia.

"The key for me to be elegant, it's not only to only to have a beautiful dress, it's to be right for the occasion," he said.

But Mrs. Trump has also been subject to scrutiny. On Trump's first trip to Texas after the hurricane, the first lady's decision to wear stilettos as she left the White House was panned on social media. Mrs. Trump changed into sneakers for the arrival of Air Force One in Corpus Christi.

Trump defended his wife's shoe choice, saying in an interview with former Arkansas Gov. Mike Huckabee on Trinity Broadcasting Network on Saturday that she has "taken tremendous abuse."

"She wants to look, out of respect for the White House, wants to look good leaving the front entrance to the White House. So she dresses up, she puts on formal shoes, high heels, and she leaves the White House going to Texas," Trump said.

The Smithsonian says the First Ladies Collection has been one of its most popular attractions for more than a century. It features 26 dresses and more than 160 other objects from Martha Washington through Melania Trump. The original exhibit in 1914 was the first Smithsonian display to prominently feature women.