Martina Olsson insists that she and Zayn, 22, slept together twice in Thailand, with him failing to mention 21-year-old Perrie both times.
Speaking to The Sun, Swedish model Martina, 24, said: “Perrie should not stay with Zayn any longer because he has cheated on her and continues to lie about it.
“It’s not the first time either so maybe she will walk away. He didn’t mention a fiancée. I Googled it to see if it was true.”
Martina claims that on 16 March she was invited to the villa One Direction were staying in by their security guard, where Zayn flirted with her.
She said they shared a shower together, before Zayn told her: “I want you now.”
Zayn was pictured holding hands with British girl Lauren Richardson just two days after his alleged hook-up with Martina.
However Martina said she also had sex with Zayn that night, but added that he and Lauren ‘disappeared for 30 minutes at the villa’.
After being pictured with Lauren, Zayn protested his innocence on Twitter – just days before he sensationally quit One Direction after five years in the band.
He wrote: “I’m 22 years old… I love a girl named Perrie Edwards. And there’s a lot of jealous f*cks in this world I’m sorry for what it looks like x”
A rep for him said: “Zayn completely denies any allegation that he had sex with Martina Olsson.”