Zayn Malik
Zayn MalikReuters

One Direction's Zayn Malik is believed to be parting ways with the band to work on his personal issues, which many believe include issues with substance abuse, according to a new report.

One Direction bosses have already set in place a contingency plan if Malik walks out following a tough year of "personal struggles" and "misery in the limelight," reported Daily Star, adding that Malik has been encouraged to seek professional help.

Although it is too soon to say how the band will be affected if Malik decides to quit, an insider told the tabloid that the other four members -- Liam Payne, Louis Tomlinson, Niall Horan and Harry Styles -- have all vowed to carry on as a four-piece band.

"The 1D lads have prepared extensively for concerts and studio recording work should one of them walk out. Management took the unusual step last year to guarantee the band's ever present place at the top of the charts in case one of the boys go AWOL or is unable to perform," claimed the UK tabloid citing an insider.

News of Malik's alleged issues with drugs and alcohol once again gained traction last month when the One Direction singer missed 'Today' appearance in November. Malik's absence prompted show host Matt Lauer to question his bandmates about the rumoured drug problem.

"Where is Zayn?" Lauer questioned, to which Payne said: "He's got a tummy bug so he's not very well at the moment so he couldn't make it over."

The host pushed further, saying, "There's obviously a lot of concern, a lot of fans have been tweeting overnight. There's been a lot of action on social media about him. Is it something more serious than just a minor illness? There have been rumors of substance abuse. What's going on?"

Payne stuck to his answer, saying: "No, he's just got a stomach bug. He's okay. He's just at home. He just needs to rest. He's okay."

But this line of questioning infuriated Malik, who later told The Sun: "I'm really angry and upset by what was said on the Today show. I was really ill at the weekend, that's why I couldn't fly to America."