Nicola, along with Cheryl Cole, formed a strong bond with Kimberley after finding fame with Girls Aloud on Popstars: The Rivals in 2002.
Kimberley has now penned her memoirs, featuring details of her life before and after her career with the girl band, in a book called Kimberley Walsh: My Autobiography to be released in September.
But while fans have to wait until its official release, Nicola has been given a sneak peek - and it appears she just couldn't put it down when it came to the part about Girls Aloud!
Taking to Twitter last night (14 July), Nicola revealed: "I've just finished the manuscript for @KimberleyJWalsh book. Its amazing..
"But I feel very weird. Is it healthy to read the past 11 years in one night? Laughed so much and cried and now I'm exhausted.."
Kimberley, meanwhile, has been inundated with messages from fans who literally can't wait to get their hands on a copy - although it appears some were confused over what it was actually about!
"Loving all your tweets about the book. Of course it's about my life! I've loved writing it so much can't wait for you all to read it!" Kimberley told them.
Check out Girls Aloud's video for 'Beautiful 'Cause You Love Me' below!
Will you be reading Kimberley's book? Tell us below, as the best comment from across the website each week wins £50!