Britain's Got Talent judge Amanda Holden was left gobsmacked by a naked act in the upcoming auditions.

The 18th series of the hit ITV talent show is set to premiere on Saturday (February 22), with lots of incredible acts gracing the stage for the longest series ever.

An official teaser was released on Friday (February 21) ahead of the new series, featuring a rather unusual act that left the judges and audience speechless.

The clip saw variety performer Akira appear on stage completely naked, with just a metal plate covering his modesty - reminiscent of last year's hilarious naked pose act, Tonikaku.

"Well, I didn't expect that," Ant McPartlin exclaimed. Bruno Tonioli swiftly looked away, while an open-mouthed Amanda watched on in horror as the act began.

Akira proceeded to use classic British props to hide his bits and pieces in a brilliantly bonkers audition. At one point, he hid behind an inflatable beach ball that was attached to a model bus, with the audience screaming in horror as the bus started moving across the table.

"Oh my god, it's so close!" a stunned Ant noted, while Simon Cowell began laughing in disbelief.

New clips were also released of a comedy impressionist, who also happens to be a BGT superfan, and an 8-year-old magician that whips the judges into shape with his spellbinding act.

The upcoming series will also feature lots of heart-warming singers, stunt acts and dance troupes - with a few jaw-dropping moments, too.

YouTube star and rapper KSI will be a guest judge for a few episodes, filling in for Bruno while he undertakes work commitments in the US.

KSI expressed his excitement in a statement, saying: "I'm so excited to be a guest judge for BGT. When I got the call up, I couldn't believe it. I remember watching old BGT episodes and going from being amazed to laughing my a*** off. I'm buzzing to see all the fresh new talent, and I'll be sure to leave a mark."

The show is back with a bang, airing more episodes than ever before. This year, the BGT semi-finals will air weekly, rather than every night during the May half term - extending the series to over four months long.

Speaking at a press event for the new series last week, Alesha Dixon teased the high standard of acts this year, saying: "I don't want to give it away, but I think that people are gonna be very, very happy... We're spoilt for choice this year."

Britain's Got Talent premieres on Saturday, February 22 at 7pm on ITV1