United Kingdom, Feb. 24 -- Prince William was at his "lowest" after his father and his wife were both diagnosed with cancer within weeks of each other.

William, Prince of Wales was dealt a double blow last year when his dad King Charles and his wife Catherine, Princess of Wales both started treatment for undisclosed forms of the disease and the royal was devastated by the family health crisis, according to his former royal aide Jason Knauf.

During an interview on TV show '60 Minutes Australia', Knauf explained: "It was awful, absolutely awful. It's the lowest I've ever seen him.

"Within a couple of weeks, if you're Prince William, you find out that both your wife and your father have cancer. I couldn't believe it."

Princess Catherine ...