(Susan Walsh/AP)

Former Secretary of State Hillary Clinton honored designer Ralph Lauren and highlighted one of her own accomplishments as first lady during her keynote address at a special naturalization ceremony today hosted by the Smithsonian's National Museum of American History.

The ceremony, at which 15 new immigrants from various countries including South Korea, El Salvador and Sierra Leone officially became U.S. Citizens, included the presentation of the James Smithson Bicentennial Medal to Lauren.

Clinton used the first event in a busy day around Washington to also tout the Save America's Treasures program, which she spearheaded as first lady.

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The program focused on preserving America's cultural and historical landmarks. Clinton said she founded the program after becoming concerned about the state of the U.S.'s most prized historical artifacts.

"I was worried at that time as we were approaching a new millennium that we would lose some of our most precious possessions," she said.

Clinton said she became aware that the Star-Spangled Banner that flew during the pivotal Battle of Baltimore during the War of 1812 was in "tatters" and wanted to restore the symbolic flag.

"I worried that those broad stripes and bright stars would not be here for generations of Americans to come," Clinton said, noting that Lauren "stepped up."

Lauren donated $10 million to help restore the flag and $3 million to support the Save America's Treasures program in general.

During his acceptance speech Lauren became teary-eyed while recounting his childhood in America as the son of immigrant parents.

"My parents were wonderful people, but they couldn't afford to give us clothes all the time," he said.

Clinton is making her rounds in Washington, with appearances on both CNN and Fox News, as well as making an appearance at the Vital Voices award ceremony at the Kennedy Center this evening.

ABC News' Dana Hughes contributed to this report.