According to The Sun newspaper, Gary wants to close his new TV show with an epic performance from the group.
As well as Gary and current members Howard Donald and Mark Owen, Robbie Williams is also on board.
But The Sun reports that Jason Orange might be a no show.
“Gary wanted to finish off Let It Shine with a bang and he thought a Take That reunion to close the show was the perfect way to achieve it," a source told the newspaper. “The idea is that it would also set the stage nicely for the musical to follow.
“Robbie seems very keen to get on board, so things are looking good. But in the end, Gary decided not to even ask Jason.”
The insider explained: “He felt the chances of him doing it were so non-existent that it wasn’t worth the effort.
"Jason just isn’t interested now, he has his own life away from Take That."
Let It Shine is on the hunt for five guys to perform in a new stage show based on the music of Take That and this week the finalists were chosen.
Following four weeks of auditions, this week the Top 40 boys were split into groups of eight who took the stage in all singing, all dancing performances with some familiar faces.
The boys sought to prove their worth as they collaborated with some of the UK’s most-loved artists with spectacular staging and one big song after another. All Star performances saw the guys share the stage with the likes of Busted, Beverley Knight, Melanie C, Olly Murs and Kaiser Chiefs.
At the end of each performance the judges - Gary, Spandau Ballet singer Martin Kemp, singer Dannii Minogue and guest judge LuLu - selected five boys from each group to make the live shows.
Let It Shine is back next Saturday night on BBC One with the first live show of the series.