The Spandau Ballet member, 55, was giving some feedback to Let It Shine hopeful, Scott Macauley, when he made the dig.
After listening to Scott’s rendition of the Scissor Sister’s Laura, the judges were all very impressed.
However, Dannii Minogue, 45, had reservations that the Belfast-based auditionee was more of a "solo performer".
Martin echoed those worries in his assessment.
Martin Kemp made a snide dig at Gary Barlow on tonight's Let It Shine
Martin said hopeful Scott Macauley was more of a "solo performer"
There’s always one that wants to go solo
Glancing over at Gary Barlow, 46, he explained: “It does worry me.
“When you usually have five boys in a band. There’s always one that wants to go solo.”
Martin then added insult to injury by giving the Take That frontman a good stare to ensure viewers knew exactly who the jibe was aimed at.
Gary famously departed Take That in 1996 to pursue a solo career, with limited success.
Martin gave Gary a good look so the audience would know the jibe was aimed at him
Gary famously left Take That in 1996 to go solo
Theatre talent shows through the years
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
Referencing his own career in Spandau Ballet, Martin continued: “Listen, I have it in my band as well, don’t worry about it!”
In the end, Scott was put through to the next round, getting almost full marks from the judges.
Dannii told him: “If you’re in this group then the boys will have a lot to live up to!”
Let It Shine continues next Saturday at 7pm on BBC One