Ben Thapa, who gained prominence as a singer with vocal group G4 when they appeared on The X Factor, has died. He was 42.

Thapa formed G4 with fellow Guildhall School of Music and Drama students Matt Stiff, Michael Christie, and Jon Ansell in 2004.

The cause of his death has not yet been announced, but just last week, Thapa shared a photograph on social media from Chelsea and Westminster Hospital, showing a dialysis machine he jokingly referred to as “my new dialysis friend.”

In a statement on Instagram, G4 wrote: “It is with deep sadness that we announce the sudden passing of our brother and great friend, Ben Thapa.

“Words cannot express how we all feel right now… We understand that this will be heartbreaking news for many others too, and we send you our love and support as we all remember the amazing man and the memories he has left behind.

“Ben has been such a major part of the international singing community, and he was a crucial part of our journey as a group. Thank you for your love during this difficult time. RIP Ben xxxx”

Thapa was a classically trained opera singer who performed as a low tenor with G4 from 2004 to 2018.

Born in Cambridge in 1982, Thapa sang in his local church choir and attended Hills Road Sixth Form College and the Royal Northern College of Music before transferring to Guildhall.

G4 initially entered the debut season of The X Factor in 2004 as a barbershop quartet, hoping to get a quote they could use on their posters. Instead, they were mentored by judge Louis Walsh and eventually finished second in the competition behind winner Steve Brookstein.

G4 went on to outsell Brookstein, and judge Simon Cowell admitted that after initially dismissing the group as “fat buskers,” they had emerged victorious from the show.

The group released their debut album, G4, in February 2005, which topped the UK charts. Later that same year, they released the follow-up album, G4 & Friends, featuring guest stars Cliff Richard, Lesley Garrett, and Robin Gibb.

They released three further albums, including a Christmas record, before Thapa announced in 2018 that he was leaving the group to focus on his opera career.

Last month, Thapa revealed on social media that he had undergone an “emergency” operation on his kidneys, known as a nephrostomy, at Chelsea and Westminster Hospital.