Michael Fassbender
Michael Fassbender quickly realised his mistake and apologised for swearing Facebook

All the excitement of the Alien:Covenant premiere in London seemed to get the better of its star, Michael Fassbender, who swore during an interview on the green carpet.

The 40-year-old actor slipped up during an interview with Edith Bowman as he described the difficulties he had playing the recorder for his role in the Ridley Scott film.

"I was practising that damn flute, a whistle or whatever you want to call it. It makes an awful sound," he said.

"I had two teachers and I was practising this thing and I could hear the neighbours going 'I hate it when people learn instruments it's f****** infuriating'." Realising his faux pas he said, "Sorry," before continuing: "So I had to put tissues in the air holes."

Also attending the Leicester Square premiere on Thursday (4 May) were Fassbender's co-stars Katherine Waterston, who wore a striking, low-cut embellished gown, and Danny McBride.

Describing the obstacles they encountered during the making of the film, Waterston said running in a space suit was a challenge, while McBride said he realised he suffers from claustrophobia.

Michael Fassbender
Michael Fassbender, star of the sci-fi horror Alien: Covenant Reuters

"Paul Thomas Anderson kept sending me e-mails going 'The girl in the new Star Wars movie is running really well – don't screw this up,'" Waterston said. "He was haunting me, so I was really paranoid about it. I feel like I look like a fraggle. It's scary to be chased especially when you're in a space suit that has magnets sticking you to the floor."

McBride explained: "I learned quickly that I'm claustrophobic, especially when putting on helmets. So I learned how to take deep breaths."

Alien: Covenant
Michael Fassbender and Katherine Waterston took to the green carpet in London's Leicester Square Reuters

Also attending the lavish premiere was director Ridley Scott, who has directed three of the six Alien movies - the original Alien, 2012's Prometheus and now Alien: Covenant.

He warned filmgoers that the movie will leave them on the edge of their seat: "I like making people laugh, but scaring people when it really works is fun. People here will get a very stressful evening and a sleepless night."

The sixth instalment in the Alien movie franchise the film follows the crew of the colony ship Covenant, which is bound for a remote planet on the far side of the galaxy.

Alien: Covenant
Director Ridley Scott said the latest instalment in the franchise is the most frightening yet Reuters

The team discover what they think is an uncharted paradise, but is actually a dangerous world. They are forced to attempt a harrowing escape after uncovering an unimaginable threat.

The premiere attracted a host of celebrities including Nathaniel Dean, Tess Haubrich, Kenneth Branagh, Brian Cox, Billy Crudup, Dakota Blue Richards and Keith Lemon, reports the Evening Standard.

Alien: Covenant releases on May 12. Watch the trailer below: