The Welsh group's drummer tragically died seven years ago at the age of 40, after he quit the group in 2003, and his former band mate has reflected on their friendship in 'Anyone Knew Our Name', taken from their latest album 'Scream Above The Sounds', which was released on Friday (27.10.17).
Speaking to The Sun newspaper, Kelly reflected on his best friend - who he described as his brother - and revealed they had made their peace years before he passed away.
He said: ''After he died, he was on my mind quite a lot. At shows I kept thinking about him. I'd dream about him. He popped into in my head all the time.
''One day the album was pretty much done but I had this overwhelming feeling to write about him. I'd been back to Wales to show my kids where I came from and so the writing was inspired by those memories.
''It's quite a sensitive song and was just pages of thoughts. Stuart is someone you'll never forget. He was a character that burnt very brightly. He had a huge smile and personality and he was very proud of this band -- even when he wasn't in it.''
Kelly has also reflected on the loss of iconic musician Tom Petty, who passed away earlier this month aged 66 after suffering from a cardiac arrest.
He said: ''I went to see Tom Petty & The Heartbreakers in Hyde Park in July. I always loved him because he was all about the music.
''Some people called the Heartbreakers the best bar band in the world. I loved that about Tom. I was really shocked by his death, though he'd looked a bit frail at Hyde Park but the band was f*****g amazing that night.''