President Donald Trump's wife, Melania, and youngest son, Barron, have moved into the White House, 4½ months after the president was sworn into office, the first lady's spokeswoman said Sunday.

"It's official! @FLOTUS & Barron have made the move to DC!" Stephanie Grisham, Melania Trump's communications director, tweeted Sunday night.

Stephanie Grisham's tweet

Melania Trump had continued living in Trump Tower in New York while Barron Trump, 11, finished the academic year at his New York school. Barron will be the first boy to live in the White House since 1963, when John F. Kennedy Jr. was 3 years old.

Sources told NBC News in April that the first lady had been "preparing the residence" at the White House for some time and was looking for suitable schools for Barron.

Barron — wearing a T-shirt reading "The Expert" — arrived on Sunday at the White House aboard Marine One with his parents and multiple pieces of luggage.

Melania Trump's parents, Viktor and Amalija Knav, were also on board Marine One.

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