Simon Cowell "really sad" about Zayn Malik quitting One Direction

Sinitta - who regularly appears on talent show 'The X Factor', on which the band were put together by Simon - said: "Simon just said that he's really proud.

"He's really proud and I think he's always known that this was always a reluctant thing for Zayn to do, so the fact that he's managed to stay this long and done so well, I think he's really proud of him but obviously we're really sad as well."

Zayn's big news came as a shock to 51-year-old Sinitta but she claims she "knew there were troubles" within the group - also made up of Harry Styles, Louis Tomlinson, Liam Payne and Niall Horan - and insists it was tough to convince the singer to join the band in 2010.

She explained: "I didn't know that he was going to be leaving, I knew that there were troubles but the funny thing is, Zayn, he was always the most reluctant.

"Even in the early days when we wanted them to dance and there was choreography ... he was always the shy one at the back.

"He has an incredible voice, beautiful boy, really sweet but just very, very shy and introverted so it was hard to get him to even be in the band in the first place."

Zayn - who is engaged to Little Mix singer Perrie Edwards - has quit the group in a bid to lead a "normal" life out of the spotlight, and Sinitta has praised him for being true to himself, despite insisting he will "miss" being in the band.

Speaking to ITV's 'Good Morning Britain', she added: "Zayn was always the romantic, spiritual one, always took his relationships very seriously, was always very gentle.

"I think the relationship is important to him, he and Perrie, that is a very prominent relationship for him and for that to be threatened in any way - especially when you're travelling around the world and all the stress and drama of that - you need an anchor, some stability somewhere so I think that would have rocked him a lot.

"I think he'll take time and then come back and he will miss it but at 22 how great to be able to say, 'I want to start my life how I want to now.' "

Just last week Zayn left One Direction's 'On the Road Again' world tour due to stress shortly after he was photographed holding hands with student Lauren Richardson in Thailand.

The group are to continue as a four-piece and played their first official gig without Zayn last night in Jakarta, Indonesia, but the occasion got too much for Harry who burst into tears on stage.