I Used to Be Friends with Greg Heffley

I Used to Be Friends with Greg Heffley was a fictional book imagined by Greg Heffley in The Ugly Truth. Greg 

thought if he became rich and also famous in future, Rowley will write this book to also get himself famous. It's unknown if it's going to exist or not. Since Greg and Rowley became friends at the end of The Ugly Truth, it is not likely that it's going to exist.