Among the acts performing for the judges this evening will be golden buzzer act Kyle Tomlinson and dancing policeman PC Dan.
Magician Niels Harder has already promised to wow Simon Cowell with his "dangerous stunt" which will involve host Declan Donnelly.
During the audition stage, Niels wowed viewers as he left fellow host Anthony McPartlin just moments from death as he volunteered to put his neck on the line in Niels's Guillotine of Death.
We will be following the show throughout the evening, giving you all the latest updates from the programme.
See below for all the live updates from tonight’s Britain's Got Talent semi-final on ITV.
7.58pm Head judge Simon Cowell has just branded PC Dan's first audition as "awful" and doesn't know if he can win. Unsurprisingly, his comments are met with jeers from the audience.
But it seems both Alesha Dixon and Amanda Holden disagree with him as the latter tells him flirtatiously: "Behind the uniform is a hot bobby with some dance moves."
Kyle Tomlinson won over judges on Britain's Got Talent
7.54pm Dancing policeman from Surrey PC Dan takes to the stage, he has always wanted to show a “human behind the uniform” which is why he auditioned for the show in the first place.
He appears to be on fine form with an R'n'B and pop medley that he's performing his routine to. It is certainly a step up from his audition, where he was dancing on stage by himself.
7.45pm After performing, Ant explains to the judges: "A bit of a stage issue, they couldn't hear the track, so we let them start again."
Amanda Holden appears to make reference to the Manchester attacks as she tells the choir: "After all the trauma we’ve been through over the past week, you were a breath of fresh air."
The junior choir are praised by the judges despite the initial problem but could this affect their chances?
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7.42pm Even before the first act has begun there has already been a technical gaffe as Ant and Dec are forced to take to the stage to apologise. But eventually, St Patrick’s Junior Choir Drumgreenagh's start giving a rendition of Katy Perry's Roar. It's a beautiful performance from the school choir.
7.30pm And we're off! The first live semi-final on Britain's Got Talent this year.
Simon Cowell has admitted that he is relieved that this year he and the other judges won't be making the decision, telling Ant and Dec: "Thank goodness! We get so much grief when it's us!"
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The results will be announced after all the acts have given their performances when they will face the public vote.
Britain’s Got Talent airs tonight at 7.30pm on ITV.