Barron and his mother, Melania, arrived in Washington DC Sunday, and the 11-year-old wore a J. Crew Crewcuts blue t-shirt with the words "The Expert" printed across the chest.
The $29.50 shirt was so popular that it is no longer available on the retailer's website.
ABC reached out to J. Crew and they said that the shirt first hit store shelves in 2015, and sold out a few seasons ago.
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