Fans may be surprised to know he's reasonably easy to spot.
Like Princes William and Harry, the Take That singer was revealed to be appearing in the latest instalment of the space opera well before filming wrapped, and now it's been confirmed which scene he's glimpsed in.
The 46-year-old singer-songwriter already revealed in March that he wouldn't be playing a Stormtrooper in the movie like Wills and Harry - but had a role, apparently thanks to his movie industry connections.
He said: "I’m not a stormtrooper, but I am in it.”
And now Gareth Edwards, the director of 2017's Rogue One, has told how he clocked Gary's face when rocking up to play his own role in the flick.
He told Fathatracks: "I got there and obviously they briefed everyone but I got there late, so they were like ‘stand there, put this on’.
"I went into this trench and I had no idea what was going on, and I looked to my right and it’s Gary Barlow.
"I think his wife or girlfriend [wife Dawn Ward] was there as well. You start looking down the line, it was a bit like ‘I’m a rebel, get me out of here’," he added.
This reveals that Gary appears in the last part of the film - in a scene featuring on the mineral world of Crait at the end of the film.
He played the Resistance trooper in the Battle of Crait - while Tom Hardy's role in The Last Jedi was cut from the final film and will only feature on the Blu-Ray release.
Beady-eyed fans may be able to spot Gary if they look very closely - though it may not be possible to discern where his face is until the DVD comes out.