Conor McGregor’s return to the octagon is in peril as under the very stringent US immigration law, "celebrities should not expect to receive preferential treatment by US authorities," according to leading law firm stateside.

In just ten short days, McGregor has seen his reputation shredded and his business empire crumbling as retailers in Ireland and in the UK have disassociated from his brand.

So as the fighter contemplates his next move, his comeback could very likely be thwarted by the jury verdict in the civil trial and the superstar’s own admission that he used drugs on the night of the assault.

During last month’s High Court case, McGregor admitted taking cocaine on the night he assaulted Nikita Hand.

Under cross-examination from Ms. Hand’s legal council, the Irish mixed martial arts (MMA) fighter replied "correct" when John Gordon SC stated he had cocaine in his car along with the alleged victim and another witness.

While US immigration policy can sometimes be "worked out," previous high-profile celebrities have seen themselves have to overcome many roadblocks in order to obtain a work visa.

In 2007, when she was at the height of her popularity, supermodel Kate Moss reportedly had to pass a drug test to obtain a visa to promote a perfume fragrance in the US.

The 33-year-old, who was at that time dating rocker Pete Doherty, reportedly had to submit to a drugs test after photographs of her allegedly taking cocaine were published in a British newspaper in September 2005.

In 1972 when Beatlemania was at the epicentre of the cultural revolution, John Lennon and his partner Yoko Ono lost their ability to stay in the US as they had convictions for drug use. They both fought and eventually won the case and were also to remain in America.

US policy has barred other celebrities from entering the country over admitted previous drug use.

In 2014, celebrity foodie Nigella Lawson was prevented from boarding a flight at Heathrow apparently as a result of comments she made about taking drugs while giving evidence in a fraud trial involving two of her former staff.

At the trial of two former personal assistants of her and her ex-husband Charles Saatchi, Lawson admitted taking cocaine.

The mother-of-two told jurors she took the class A drug twice, once with her late husband John Diamond when he found out he had terminal cancer and again in 2010 when, she said, she was being ‘subjected to intimate terrorism’ by her then partner Charles Saatchi.

Lawson was subsequently invited to the US embassy in London where she was granted permission to reapply for an entry visa.

So as Conor McGregor hopes to regain his status and riches, his High Court admission could see him literally hoisted by his own petard.

*This article was originally published on Extra.ie.