Round-up: Thursday's semi-final was a corker!
Simon said it was his favourite semi-final so far, and Thursday's show was full of twists and turns, and even a few tears, curtesy of Lisa Sampson and The Neales.
But only two acts could go through to the final, and the public voted young crooner Isaac Waddington the big winner of the night, while the Judges chose family band The Neales to join them on Sunday night.
They'll be battling it out against Jamie Raven, UDI, Jules O'Dwyer and Matisse and Old Men Grooving, Côr Glanaethwy and Entity Allstars.
Check out our other amazing semi-finalists here:
These acrobats, free runners and dancers opened the show with an energetic routine for their semi-final performance, although they had mixed reviews from the Judges.
"I am completely underwhelmed if I'm honest," said Simon.
Alesha agreed, "it didn't blow me away," she said, although David seemed to enjoy himself.
"I love how you fuse all the different things you do," he said.
Lisa Sampson's retro-themed hula hoop performance lit up the BGT stage, although a few tiny mishaps left the talented twirler in tears at the end. But the awesome foursome rallied around to cheer her up.
"We didn't know what you did wrong so don't tell us! It looked absolutely perfect!" said Amanda.
"You set fire to yourself, you turned into a slinky... You're so likeable, I think the public probably will get behind you," added Simon.
The Kanneh-Masons' rousing medley of classical and contemporary music brought the house down on Thursday's show.
"I just think as a family of musicians, you're absolutely extraordinary," said Amanda. "You give this music personality."
"You know what guys, when you've got it, you've got it. I love the arrangement, I can see this act going all over the world. You could be the most talented family in the world," said Simon.
The Neales' emotional semi-final performance had the Judges reaching for their hankies, and Simon's mascara was even running! And it was enough to bag them a spot in Sunday's final!
"I actually got quite emotional, what's happening to me!" said Simon. " It was a perfect song, I really like you guys."
"People are gonna make a connection with you, as the most important thing in the world is family," added Alesha.
She's been battling tonsillitis all week, but that didn't Maia Gough giving it some serious welly on Thursday night. Her powerful rendition of Whitney Houston's I didn't Know My Own Strength wowed the Judges and the audience.
"You're an ordinary little girl... and then something extraordinary comes out of your mouth when you sing," gushed Amanda.
Simon added: "you've got tonsillitis and you decide to sing on live TV one of the hardest Whitney Houston songs - and it worked. I think you did fantastic, well done."
Jeffrey took Chantel to Mars for his bonkers semi-final performance. Simon hit his red buzzer, but that didn't stop him earning a standing ovation from the delighted audience!
"I really, really like you," said Simon. "But I think you win the award for the worst act we've ever had on the show."
The other Judges loved his barking mad performance, though.
"I would love to see you in the final," said David.
Marc Métral and Miss Wendy were feeling mischievous during their semi-final performance, and Simon was utterly charmed.
"I want Wendy, can I buy her?" he asked. "I could see her maybe winning this show."
"It's the most unique, funny act that we've seen for a long time on BGT," added Amanda.
Isaac Waddington was in exceedingly fine voice on Thursday's show, bagging a standing ovation from all four Judges - and a place in the final - following his beautiful rendition of I Can't Make You Love Me.
"You've got a great voice, great taste in music... this for me was a big step up. It was a fantastic, fantastic performance," said Simon.
"I find your voice very hypnotic. That was perfect vocally and I want your album," added Alesha.
Ant and Dec were proud as punch after their golden buzzer act Boyband put on a magnificent display in Thursday's semi final, but they narrowly missed out on a spot in the final.
"It's really hard, just five people, but it just works," said Simon. "It feels really current, really relevant."
"You're real contenders in the competition this year guys," said Alesha. But sadly, it wasn't to be.