Wladimir Klitschko

The former heavyweight world champion boxer says he has been left "deeply saddened" by the passing of his former partner – whom he has daughter Kaya, 11, with.

In a statement on Instagram, Klitschko wrote: "Our family is going through a time of profound shock and grief.

"The announcement of Hayden’s tragic death saddens me deeply. She left this world far too soon. Hayden was, although no longer my partner, an important part of my life and the mother of our daughter, Kaya."

The legendary Ukrainian fighter said that he will "always" speak with Hayden "with respect" when discussing her with their daughter and will ensure that the youngster remembers her mother.