Biffy Clyro bassist James Johnston has quit as he seeks professional help for addiction and mental health issues.

In an announcement on Monday, the band explained that he would no longer be joining them on their upcoming tour.  

The rock band are formed of Simon Neil, James and his twin brother Ben, with other musicians joining them for live shows. 

In the statement, shared to Instagram, James explained: 'I am heartbroken to let you know that I will not be joining the band on the upcoming tours.

'For some time, I have been living with mental health problems which have led to addiction issues that I have kept concealed for a long time.

'This has caused significant problems for myself and everyone around me - the time has come to properly address my illnesses and deal with them.' 

He continued: 'I am extremely sorry to Ben and Simon and thank them for their continued love, patience, support and understanding throughout this time. 

'I have recently started to receive the professional help that I need and assure you that there is light at the end of the tunnel. 

'To all our fabs, your support means so much to me and in the meantime our dear friend Naomi McCleod will be taking care of bass duties, and I cannot think of a better person for the job. With love, James.' 

The band will kick off their next tour in January, starting in Belfast before making their way over to Europe. 

They then have a sting of shows in Australia and  New Zealand before heading back to the UK for festival season for Leeds and Reading, Download, Isle of Wight and  TRNSMT. 

The band released their 10th studio album Futique in September, but frontman Simon has already been busy penning new material and revealed he's been experimenting with different sounds, including garage rock and country rock.

He told NME of the new tunes: 'They’re less focussed, as always. I like the beauty of the fact that these other songs have been worked on less so there’s more freedom. 

'They’re flapping the breeze and we can focus on our eccentricities. There’s a liberation in knowing that people who are really into our band will listen to them at this stage. It fills the story and completes our picture.'

Simon added: 'There are some garage rock songs on there, one of the best country rock songs I’ve ever written.' 

Fans will have to wait and see if the new tracks make it onto their next album.

The prolific songwriter says Biffy plan to stick around for years to come and making Futique made him realise it's far from 'the end of the road' for Scottish trio.

Simon added: 'I know that’s ludicrous to say on your 10th album, but we’re still on this f****** journey. We’re still finding new ways to do s***.'