Blue refuse to sit next to each other on planes.
The boyband – comprised of Duncan James, Lee Ryan, Simon Webbe and Antony Costa – formed in 2000 and still share a dressing room on tour but Duncan revealed the one thing they refuse to do.
He told The Sun: “The only thing we don’t do is sit next to each other on an aeroplane.
“We all like a window seat and so we all want that seat, and if you don’t get a window, it’s like ‘Oh for God’s sake!’, that’s when you could have an argument!”
Apart from squabbles over window seats, Duncan insisted he and his bandmates “never really argue” and are like brothers.
He said: “For me, I think it’s because we have a lot of loyalty to one another. And I think boys as well, we never really argue.
“We don’t have these b***** squabbles about clothing or who is going to have what.
“But I think honestly, it’s probably down to the fact that I’m an only child, so I never had any brothers and sisters.
“So when I got into Blue and at the height of it all it was just crazy, we were all over the place around the world, doing songs with Elton John and all that, and I think you just become really close like brothers.
“They’re brothers that I never thought I’d ever have, and we’re family. We always say that to each other, we’re family. And I think that’s the key.
“There’s been a lot of stuff that’s gone on and we’ve always stood by each other and supported each other, and that’s what families do, don’t they?”
And, Duncan is excited for the band to release their new album Reflections and go on tour to celebrate 25 years together.
He said: “We’re very busy with the new album Reflections coming out. Then a big world tour for our 25th anniversary. I just can’t believe we have got to 25 years and we’ve never lost a member.
“We’ve stayed together for 25 years and we’re still there.”