His death was announced on Twitter via the band’s official Twitter account today.
The singer’s cause of death is currently unclear.
However it is understood that he was battling skin cancer after being diagnosed in 2016.
The Daily Star have reported that he has died after falling from a balcony in London.
The tweet read: “It is with the greatest sadness that we have to announce that our dear friend and brother Timmy has passed away.
“We know this news will be as heartbreaking for you all as it is for us.
“We appreciate your love and support at this difficult time. Mike, Darren, Mark & Lachie x.”
In a 2016 statement about his illness, Timmy said: “I need to share some news with you about something that is going on in my life at the moment. I’m devastated to actually be writing this but unfortunately I won’t be able to join the boys on the road for this Christmas tour.
“In Sept this year I was diagnosed with melanoma (skin cancer). In October I had an operation to remove some lymph nodes and had hoped that would be the only treatment required. But just recently more lumps around my collar bone and neck were discovered which will need further, ongoing treatment.
“As you can imagine it’s been a big few months. It’s been a tough and heartbreaking decision to make but I have to focus on getting better and taking care of my health.”
He returned to the band in 2017 to continue touring.
Timmy recently set up a JustGiving page online, where he was planning on skydiving 15,000 feet.
The jump was in aid of raising money for the hospital where he received his cancer treatment, The Royal Marsden in London.
He was due to make the jump on 3rd May this year.
So far he had raised €6,000 for the hospital.
Timmy originally resides from Cork, Ireland.
He became a member of the band in 2010.
The band have had four top-ten albums in the UK.
Tributes have poured in from celebs, including Phillip Schofield and Sam Bailey.
Phillip said: “I’m so terribly sorry to hear this and sending lots of love to you all and particularly Timmy’s family and his many friends.”
