United Kingdom, Feb. 5 -- Kate Cassidy left Liam Payne in Argentina in order to take care of their dog.

The One Direction star passed away in October, aged 31, after falling from his hotel balcony in Buenos Aires, and Kate has now revealed why she left her boyfriend in the Argentine capital while she returned to the US.

Kate, 25 - who co-owned a rescue dog, called Nala, with Liam - told The Sun newspaper: "I had a responsibility, we had a responsibility. We had our dog and obviously I never, ever thought this event would occur.

"It was a tragic accident and no, I never did think (he might die young). But, you know, we did have our own separate lives - this wasn't the first time we have travelled separately.

"I just never thought this ...