In the show, viewers learnt that Dion had decided to audition for the BBC One talent competition after Gary visited him at his home in Wales and told him he had a chance.
The audition seemed to go well as Dion sang McFly's All About You to cheers from the live studio audience.
Unfortunately, when it came to the scores, the Welsh hopeful was just one star away from the finish line, which meant he could not progress through to the next round.
Intending to cheer him up about just missing out, Gary, 46, advised Dion to get some experience before trying again.
Gary Barlow gave some advice to aspiring singer Dion on Let It Shine tonight
The aspiring singer had been inspired to audition after Gary visited him at his home in Wales
Dion fell just one star short of progressing to the next round of the BBC singing competition
Please, please go away
The Take That frontman said: “Please, please go away. Take this experience. Learn from it.”
But to many viewers at home, Gary's choice of words sounded more like an insult rather than constructive criticism.
One social media user said: “‘Please, please go away.’ Nice Gary. Nice.”
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Gary told Dion to "please, please go away"
The best musical talent shows
Wed, November 16, 2016
As Gary Barlow launches new talent show 'Let it Shine' to find the stars of a Take That musical, we look at the successful musical theatre talent shows of the past.
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Let it Shine – The new BBC show will see Gary Barlow looking for five young men to star in a new Take That musical
“As Gary said ‘Please please GO AWAY’,” another remarked.
While a third added: “‘Gary, any words of encouragement?’ ‘Go away’ Harsh.”
Earlier on in the episode, fans were left gobsmacked as a Robbie Williams look-a-like auditioned to be part of the new musical.
Let It Shine continues next Saturday at 7pm on BBC One.