The 41-year-old singer has seen the band - made up of himself, Mark Owen, Howard Donald and Jason Orange and occasional member Robbie Williams - break up in 1996 before a well-received reunion in 2005, and while they are not always together he envisages they will remain close forever.
He said: ''I talk to the lads about once a week, including Rob. Yeah, we had the fallout, but he's different now.
''In fact, we all are. And I'd love to think we'll be mates for the rest of our days.''
Gary admits he was terrified when the band got back together because he thought they would get ''slated'' but was delighted when the public embraced them.
He added: ''I still can't believe how positive the public were when we got back together! I thought we'd get slated.
''Outside, I was all gung-ho, but inside I was bricking it. I'd love to be more thick skinned by I'm not. That's why I got down when people had a pop at my solo stuff. But I didn't tell anyone. I'm like my mum, tough exterior, not so tough inside.''