The 48-year-old frontman - who is joined by Howard Donald, 50, and Mark Owen, 47, in the 'Never Forget' group - has reassured fans that their upcoming 30th anniversary tour does not spell the end of the band and admitted he feels like they are ''just over half way'' through their career.
Gary told The Sun newspaper's Bizarre column: ''The end? Absolutely not.
''The other day I thought 'Do you know what, we're probably just over half way through the story.
''I think there's loads more still to come.''
The 'Shine' hitmakers - who have 12 number one singles to their name - are more focused on the future than ever before.
Gary continued: ''We've been quite an ambitious band in the past.
''We've always wanted more No1s and now that's the ambition just to continue.''
Howard also confessed that if he started to lose his luscious thick mop of curls, he wouldn't want to be a pop star anymore.
He admitted: ''That's all I've worried about since 21 because a couple of my brothers have really receded.
''I'm like, 'God, I really don't want to look like them, I won't be a pop star anymore.'''
There had been talk of both of them rejoining the group for the special milestone.
However, Robbie - who quit Take That in 1995, a year before they originally split, and rejoined from 2009 to 2012 - admitted that although he would have loved to mark three decades of the band, he'd only be willing to do it if Jason came back after leaving in 2014.
He said: ''I'm up for it. But I don't know what their calendar says, what my calendar says. I don't know what their manager says.
''We'd all love to do it. I'd love to get Jason back involved, realistically I don't think so.
''If we could get Jay back it would be perfect.''
His new album Underneath It All is out now.