The two acts received the highest number of votes from the public with The Pensionalities getting the most.
Tonight there were performances from teen singing sensation Reuben Gray, John Parnell, Paws with Soul, Angelicus Celtis, Jonny Awsum and Ryan Tracey.
The winners will be joining Kyle Tomlinson, mind reading act DNA, magician Matt Edwards, Issy Simpson, Tokio Myers and comedian Ned Woodman.
There was shock last night after Simon Cowell’s Golden Buzzer act Sarah Ikumu did not make it through to the final, leaving the music mogul stunned and speechless following the announcement.
Tomorrow will mark the last of the semi-final shows when the judges will also chose a wildcard act to go through to the final.
The final will be taking place on Saturday after ITV moved the programme out of respect for the Ariana Grande concert to commemorate the victims of the Manchester bombing.
MerseyGirls will be performing on Britain's Got Talent this evening
In a statement, an ITV spokesman said: “Ariana Grande’s One Love Manchester benefit concert is bringing artists and the public together, and will raise funds for the Red Cross’s Manchester Emergency Fund.”
“ITV and Britain’s Got Talent have no desire to distract from this important cause, so we have taken the decision to move the Britain’s Got Talent Final from Sunday night.”
We will be following all the action from the fourth semi-final show.
See below for all the live updates from tonight’s Britain's Got Talent semi-final on ITV.
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Dance act Just Us get the golden buzzer
10pm The MerseyGirls and The Pensionalities are through to the final.
Sadly Reuben Gray does not make it through, telling Ant: "Thank you for the opportunity, it's been the best experience of my life."
9.59pm What distracted Simon so much? He was deep in conversation with the rest of the panel.
9.56pm Sadly, the Hoop Guy has failed to make it through – but Alesha is probably relieved.
9.55pm The anticipation is building as the results are announced and it is nail-biting one.
9.54pm David is back the Hoop Guy but Alesha is not having any of it.
"Mystic Mandy" is sticking the acts she named at the beginning of the show: The Pensionalities and the MerseyGirls.
9.44pm Reigning Britain's Got Talent champion Richard Jones does some magic tricks for the audience as we await the results.
9.30pm We're back and the results will be announced shortly!
The Merseygirls closed the performances on Britain's Got Talent
8.56pm All the acts have performed this evening and now the vote is open.
8.54pm Alesha has nothing but praise for her act as Amanda says: "I can see your faces come alive when you dance."
"Whatever happens, you're going to be in a great position," Simon assures them. Could they be the wildcard?
8.51pm This could be one of the most emotional performances of the evening as one member of the dance troupe may never be able to dance again.
8.43pm There is one act left this evening: The MerseyGirls, Alesha's Golden Buzzer act.
8.37pm David Walliams is roped into a performance with Jonny Awsum – the Little Britain comedian does not look pleased at the prospect of playing the triangle.
Jonny Awsum is doing a rap about Croydon called The Triangle Song and the audience are getting into it as is David.
"Well, that was unexpected," Alesha starts: "It was very different. I like the way you take the mickey out of things and you are such a loveable guy."
Jonny Awsum and David Walliams perform on Britain's Got Talent
8.27pm The Pensionalities are going to be up next and are set to warm hearts with a big number. They have hilariously gone for a One Direction song given a jazzy re-vamp.
"I just love you guys so much! I have the upmost respect for you!" Alesha says them, while Amanda says it was the best performance of the week.
Simon also has nothing but praise for the twosome: "I have a feeling we are going to see you on Saturday night."
8.21pm There is a mixed response from the panel and Amanda gets booed as she suggests that Ryan can't got much further.
8.17pm He is really going for it and the crowds want him to succeed. Sadly he matches the record but fails to beat it – it all seems a bit strange.
A schoolgirl choir from Wales opens the show on Britain's Got Talent
8.15pm From hoops to balloons as Ryan Tracey tries to break another world record by making the most shapes in one minute. The current record stands at 13 and was set back in 2005 and has not been beaten for 12 years.
8.09pm Reuben Gray sings a self-penned song for his girlfriend in a stripped-down performance.
Simon does not the like the song but David and Amanda are the opposite, congratulating him on it.
8.03pm John Parnell – the Hoop Guy – is sending the crowds mad but not Simon who has just buzzed him out.
Alesha is also very displeased by her strange sampling in the song, telling him: "Any Mis-Teeq crediblity has just gone."
Alesha Dixon was not impressed with John Parnell after she made an appearance in his song
7.49pm Schoolgirl choir Angelicus Celtis take to the stage once more and sound truly heavenly.
The crowds have gone wild and the judges are standing up but can this be enough to win them a place in the finals.
"I hope people pick up the phones to you, I would love to see you in the final," says Alesha Dixon.
Simon thinks they have "a shot" but David disagrees and says: "The royals would absolutely love you."
He then adds cheekily as he looks at Amanda Holden: "None of you are wearing a really inappropriate low-cut top."
Singer Reuben Gray will be performing on Britain's Got Talent this evening
7.38pm We kick off with Paws with Soul, who give an energetic routine that is slick and whacky at the same time.
"I wouldn't be surprised if loads of kids pick up their parents' phone with their parents' permission," says David Walliams.
But Simon is not convinced as he says it was "good-ish" and is struggling to see where the act could go in the future.
7.36pm Simon reflects on the shock elimination of Sarah Ikumu, saying: "I'm glad that the two went through." It is clear he is still disappointed but hints that the schoolgirl could be the wildcard.
7.33pm The judges make their appearance and Amanda Holden has opted for a plunging and sparkly number that is likely to have viewers talking.
7.30pm And we're off again!
Britain’s Got Talent is on ITV tonight at 7.30pm.