The 31-year-old recently announced that she is working on a tell-all book after the band's surprise split in March, reported Contactmusic.
"When Girls Aloud broke up in March it was such a definite end of an era in my life that I thought it would be a lovely way to tie the whole thing up and finish that chapter... It was quite hard (to recall everything). I've had to search the internet for places and dates, but Justin is good at jogging my memory," Walsh said.
"I'll give them their bits to read and hopefully they'll be fine," she added.