Melania Trump’s parents have been sworn in as US citizens.
The Slovenian couple visited a US federal building for an hour-long meeting on Wednesday in New York which houses offices for federal immigration officials to help process citizenship applications.
A lawyer for Viktor and Amalija Knavs said the couple took the citizenship oath on Thursday in New York City. He confirmed the First Lady had sponsored their green cards.
The decision is likely to cause outcry following Trumps comments to end family-based immigration which he referred to as "chain migration".
Trump's in-laws had been living in the US as permanent residents.
The Knavses raised Melania in the rural industrial town of Sevnica while Slovenia was under Communist rule.
The first lady, born Melanija, attended high school in the Slovenian capital, Ljubljana, and changed her name to Melania Knauss when she started modelling.
Her father - who is 74 and two years older than his son-in-law - was a car dealer, while his wife, worked in a textile factory.
Melania settled in New York in 1996 and met Donald Trump two years later before they married in 2005.
Donald Trump hasn't commented about his in-laws newfound American citizenship.