Let It Shine went live on BBC One tonight and did so in style, but not everyone was impressed.
The groups opened the show - with the help of Gary's fellow judge Martin Kemp - with a Pitch Perfect style riff off.
They belted out hits including This Is How We Do it, Hot In Herre, No Diggity, Hey Ya and more.
Some viewers absolutely LOVED the mega mash up of hits, performed acapella.
"That's the first time I have been impressed by one of these programs. That opening! #LetItShine #niceone," wrote one fan.
Another agreed: "Love the pitch perfect type opening 👌🏻 #LetItShine"
And a third tweeted: "This opening to the show tonight was so good #letitshine"
But for others the performance brought out some really strong emotions of the not so positive kind.
"Wow. You read stuff by Donald Trump & think the world is bad. Real bad. But then you turn #letitshine on on the TV and there are no words," wrote one unhappy viewer.
Another went on: "What the hell is going on with @BBCOne and #letitshine I've never felt so violated in my life!!! You ditched the voice for this? #WowJustWow."
In the second half of the night's double live show, five boys went home leaving four groups in next weekend's semi-finals where they'll perform with Take That.
Let It Shine returns next Saturday night on BBC One.