Dougie Poynter has admitted that he became addicted to valium in the wake of McFly's break-up in 2016.
One of the UK's most successful and beloved groups, the four-piece went on hiatus four years ago after 13 years together as a band.
Now they have reunited for new music and a new tour in 2021 and speaking on the one-off documentary McFly: All About Us, 32-year-old Poynter revealed that he struggled to cope without being around bandmates Tom Fletcher, Danny Jones and Harry Judd on a daily basis.
"On the one hand I felt inspired because friends in LA would take me to see other bands and stuff," he said.
"On the other hand, I was like, 'But my band's broken and it's all my fault'. Valium was a way of just making all that disappear."
Judd added: "I said to him, 'Don't freak out mate, but I know you're taking something. Is everything OK?' And he sort of told me what he'd been taking. He was like, at that lethal dosage."
"Doug's parents had split and he moved in with the band at 15," said Fletcher, 35. "We're all he had to cling on to when there were tough things going on in his life."
McFly: All About Us airs Saturday at 6.40pm on ITV.