Zayn Malik is ''angry and upset'' after being accused of having a drug problem.

The 21-year-old singer is ''gutted'' to have missed a promotional trip to America to plug One Direction's new album 'Four' after falling ill at the weekend and was horrified when his bandmates were quizzed on live TV about the unsubstantiated allegations.

He told The Sun newspaper: ''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.

''As soon as I'm feeling better I'm going to join the guys and carry on with the promotion for the album.

''I was gutted to have to miss album release day. But I'm going to be back as soon as I can.''

The 'Steal My Girl' hitmaker spoke out after 'Today Show' host Matt Lauer queried his absence, asking the rest of the group: ''There have been rumours of substance abuse, what's going on?''

As watching fans booed, Niall Horan shook his head in anger while Liam Payne replied: ''No, he's just got a stomach bug, he's OK. He's just at home. He just needs to rest. He's OK.

''We only found out this morning, so we're really sad, he is as well, that he can't be here for our album release.''

Zayn - who was the subject of a leaked video earlier this year in which he appeared to be smoking a marijuana-laced cigarette - recently missed another group commitment, leaving Liam, Niall, Harry Styles and Louis Tomlinson to shoot acceptance speeches for the three MTV Video Music Awards (VMAs) they won earlier this month without him.