In a new BBC documentary the star explains he is still haunted by failing to tell the others he had taken the lead on chart-topping track Relight My Fire, and says: "I just did it in a way that upset people."
Gary - who last year rejuvenated his solo career - tells actor James Corden that he stepped in when Robbie, who had been earmarked for the main role, was struggling with the song.
In the BBC One film When Corden Met Barlow, to be screened next week, he says of Robbie: "H e went in and I got a call from the producer late in the night saying 'we've had him in all night and it's just not working'.
"And so the next day I just thought I'm just gonna do it. In defence of everyone else I should have just said to everyone, I'm going to go in and do a vocal today. There's a few things in that time which, believe me, still come up. I just went in bang and I did it."
Robbie went on to leave the group in the mid-1990s and there was a deep rift between him and Gary for many years until they eventually buried the hatchet after almost a decade and a half, cementing their bond with a joint single and Robbie's eventual return to Take That.
In the film, to be screened on May 5, he also talks about how he had little interest in joining a group but, aside from having to dance, he enjoyed the camaraderie when he attended the audition for manager Nigel Martin Smith.
" The dancing was the bit I was dreading the most. I didn't really want to be in a band if I'm honest, but there was something there, I liked being part of a team that day. I liked being up there all together, all going through the same thing."