Little Mix have revealed that it was hard at times to revisit the past when writing their new book.

The girl group have just released Our World, which looks back at the singers' evolution.

Speaking to Maximum Pop, Jesy Nelson admitted it felt odd to look back in the past.

She said: "It’s weird when you have to relive certain things. It can be really emotional to go back to a time which wasn’t very nice for you.

"It was hard for all of us but at the same time it was like therapy."

Jade Thirlwall added: "It’s quite a relief when it’s out there."

When asked why they decided to write the book, Nelson replied:

"We just love the fact that our fans relate to us so much and that young girls will read this who are going through the same thing. I know that I’ve come out the other end a better person and that’s what we try to do with our music so it’s great to be able to do it in a book."

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Watch Little Mix's latest music video below: