"If I did this by myself it would be a lot more difficult"
"Simply because having four other people that do exactly the same thing as you, go through exactly the same experiences, have the same life experiences to a certain extent because you've lived the same life for the last three or four years is a really useful thing.
"It is cool to have that and it would be more difficult to be a solo artist I think. Sometimes I do look at solo artists and I feel a bit sorry for them because they don't have that, whereas we have a proper camaraderie."
for anyone who doesn't think he has the voice for it - vid1, vid2, vid3, vines
EDIT: Removed source material