Celebrity chef Nigella Lawson, who acknowledged last year that she had occasionally used cocaine, was denied permission to board a flight to the United States over the weekend, the US Embassy said.
The embassy did not disclose the reason for refusing Lawson entry into the United States.
Embassy spokeswoman Lynne Platt said on Thursday (local time) that Lawson was stopped from travelling on Sunday and had subsequently been invited to the embassy to apply for a visa. She said such applications were generally handled "routinely and expeditiously."
Lawson tweeted Saturday that she was going on vacation, but she also has worked in the US, where she co-hosted TV cooking competition The Taste.
British citizens need visas to work in the US but not for a vacation.
US Customs and Border Protection said privacy laws meant it was "not at liberty to discuss an individual's processing." It said US authorities may refuse passengers admission for various reasons, including drug use and "moral turpitude."
The agency said 366 people a day were refused entry to the US in 2013, of almost 1 million daily travellers.
Lawson, author of How To Be A Domestic Goddess, has had a turbulent year in which her personal life was scrutinised in the media.
In July she divorced art collector Charles Saatchi after he was photographed grabbing her throat outside a London restaurant.
In December she testified at the fraud trial of two former aides, and told the court she had used cocaine a handful of times. She denied claims by the defendants that she was a regular drug user.
"I promise you ... regular cocaine users do not look like this," said Lawson, who is known for her voluptuous figure.
Police later said they would not be investigating Lawson.
Lawson's co-host on The Taste, chef Anthony Bourdain, tweeted that he was "absolutely mortified with embarrassment over the cruelty and hypocrisy of US actions" over Lawson's travel.
Bourdain told The Associated Press in an email that Lawson was "the most focused, non-party, sober person I know. How this could happen - to her, of all people - is beyond me."
A spokesman for Lawson declined comment.
She is not the first British celebrity to fall afoul of US immigration officials. In 2008 the late singer Any Winehouse, who had a marijuana arrest and well-publicized problems with alcohol and drugs, was refused a visa to perform at the Grammy Awards.
Singer Lily Allen was denied a visa the same year, shortly after she was arrested over an altercation with photographers.