Celebrity chef Nigella Lawson, who has admitted past drug use, was denied permission to board a flight to the United States on Sunday, the U.S. Embassy spokeswoman Lynne Platt said Thursday.

The embassy did not disclose the reason Lawson was not allowed entry into the United States.

According to Platt, Lawson was stopped from traveling on the Los Angeles- bound flight on Sunday, and that she was subsequently invited to the U.S. Embassy to apply for a visa.

“Applicants for admission bear the burden of proof to establish that they are clearly eligible to enter the United States,” Platt said in a statement.

“In order to demonstrate that they are admissible, the applicant must overcome all grounds of inadmissibility,” the statement said.

The day before, Nigella posted a tweet noting she was planning on traveling to the U.S. for vacation.

Off line for a while enjoying the ultimate; a holiday break with no signal! Will miss you all though. Know I will be eating on your behalf

— Nigella Lawson (@Nigella_Lawson) March 31, 2014

British citizens are required to have a visa to work in the U.S., but not to go on vacation.

In December, Lawson testified at the fraud trial of two former aides. She told the court then that she had used cocaine a handful of times, and denied claims by the defendants that she was a regular drug user. Police later said they would not investigate Lawson.

Lawson, 54, worked in the U.S., where she judged contestants on the ABC prime time cooking show The Taste alongside Anthony Bourdain, 57, for two seasons. Bourdain, who is Manhattan-based, took to Twitter on Thursday morning to rant about Lawson being denied entry to the U.S.

I am absolutely mortified with embarrassment over the cruelty and hypocrisy of US actions re: #Nigella travel. Unbelievable.

— Anthony Bourdain (@Bourdain) April 3, 2014

“There are several ways of legally traveling into the United States, and Ms. Lawson has been invited to come to the Embassy and apply for a visa for travel to the U.S.,” Platt reportedly said Thursday.

“We understand she has professional requirements for U.S. travel and these matters are generally handled routinely and expeditiously, so stand by,” the spokeswoman said.

Image via Wikimedia Commons