Actor Charlie Heaton has apologized to fans for missing the Stranger Things season two premiere party after he was denied entry to the U.S. over drug allegations.

The British star was detained at Los Angeles International Airport on 21 October (17) and then deported back to the U.K. after authorities reportedly found traces of cocaine on his wallet during a random bag check.

As a result, Heaton was prevented from joining his TV castmates at the Stranger Things season two celebration last week (26Oct17), but he has now assured fans he is doing his best to clear up the immigration problem.

"My planned travel to the U.S. last week was affected by an issue at U.S. immigration, and I am working to rectify it as soon as possible," he shared in a statement released on Monday (30Oct17), insisting he was "not arrested or charged with a crime, and cooperated fully with the U.S. officials at LAX".

"I'm sorry to all the fans and my Stranger Things family for missing the premiere," Heaton continued. "We are all so proud of this season and I would never want this story to negatively impact the show."

While Charlie didn't address the drug possession allegations specifically, his relatives have spoken out to protest the claims.

In an interview with the Daily Mail, his sister Kaayleigh Heaton revealed the actor had provided officials with various samples to be tested for drugs in a bid to prove his innocence - and they have all reportedly come back negative for illegal substances.

"He is racking his brain about how this could happen," she said. "He hasn't done anything, he wasn't carrying anything...

"He has had hair sample, a blood test and urine sample which are absolutely clean. A hair sample can last up to five months so that proves he hasn't taken anything."

Heaton's mother, Michelle Lowe, also insisted her son has "never done drugs", telling the publication, "All that rubbish (reports of his drug use), it's completely fabricated."

"He has proven his innocence (undergoing tests)," she continued, claiming Charlie likely picked up the cocaine residue without his knowledge by putting his wallet down during a night out. "It could happen to any of us, you go to a bar or a party. It's just unfortunate really. I know that's what has happened. I hope it blows over."

Kaayleigh went on to accuse U.S. airport authorities of purposefully targetting Charlie, 23, because of his fame as Stranger Things character Jonathan Byers, and alleges they failed to follow the proper legal procedures and allow the actor access to a lawyer.

She added, "They didn't follow procedure. I think they saw him, they noticed him and they used him as a target.

"He wasn't carrying anything, he wasn't under the influence of any drugs. I think it's just a misunderstanding."